Feed energy evaluation for growing pigs

Correlation between reproductive performance and sow body weight change during gestation

This study investigated the correlation between piglet performance and sow body weight change (BWC) during two gestational periods: 35-70, 70-105, and 35-105 days. A cohort of 70 sows was evaluated for BWC, backfat thickness change (BFC), caliper score change (CALC), feed intake, and weaning-to-estrus interval (WEI). The collected data were then analyzed according to the two specified periods. Our findings highlighted that piglet birth weight, weaning weight, and average daily weight gain (ADG) correlated with sow body characteristics, including BFC and CALC. The strongest correlation was observed with BWC. Piglet mortality was intimately associated with BFC. Piglet birth weight, weaning weight, and ADG showed a positive correlation with sow BWC, particularly during the 35-70 day period. Furthermore, sows displaying a higher BWC during the 70-105 day period, and also exhibiting a higher BW gain from 35-70 days, registered greater piglet weight gains and higher weaning weights. These trends became more apparent as the sow's BWC increased during the 70-105 day period. Piglet mortality increased when the sow exhibited a lower BWC during both the 35-70 and 70-105 day periods. No significant observations were found concerning the number of stillborn piglets, live-born piglets, or weaned piglets, and no interaction effects were detected between these periods. In conclusion, our findings underscore the significance of sow BWC during the early stages of gestation (d 35-70) for enhancing piglet performance from birth to weaning.

Effect of different feeding strategies and dietary fiber levels on energy and protein retention in gestating sows

The aim of the study was to investigate whether increased inclusion of sugar beet pulp (SBP) alters retention of fat, protein, and energy when backfat (BF) is restored in early- and mid-gestation. In total, 46 sows were fed one of four dietary treatments with increasing inclusion of SBP providing dietary fiber (DF) levels of 119, 152, 185, and 217 g/kg; sows were assigned to one of three feeding strategies (FS; high, medium, and low) depending on BF thickness at mating and again at day 30 for the following month. On days 0, 30, 60, and 108, body weight (BW) and BF thickness were measured and body pools of protein and fat were estimated using the deuterium oxide technique. On days 30 and 60, urine, feces, and blood samples were collected to quantify metabolites, energy, and nitrogen (N) balances. On days 15 and 45, heart rate was recorded to estimate heat energy. At farrowing, total born and weight of the litter were recorded. In early gestation, BW gain (P < 0.01) and body protein retention increased (P < 0.05) with increasing fiber inclusion, while body fat retention increased numerically by 59%. The increase in BF was greatest for sows fed the high FS, intermediate when fed the medium strategy, and negligible for sows fed the lowest FS (P < 0.001). Nitrogen intake, N loss in feces, and N balance increased linearly, whereas N loss in urine tended to decrease with increasing inclusion of fibers in early gestation. Concomitantly, fecal energy output and energy lost as methane increased linearly (P < 0.001), while energy output in urine declined linearly. Total metabolizable energy (ME) intake therefore increased from 36.5 MJ ME/d in the low fiber group to 38.5 MJ ME/d in the high fiber group (P < 0.01). Changing the ME towards more ketogenic energy was expected to favor fat retention rather than protein retention. However, due to increased intake of ME and increased N efficiency with increasing fiber inclusion, the sows gained more weight and protein with increasing fiber inclusion. In conclusion, increased feed intake improved both fat and protein retention, whereas increased DF intake increased protein retention.

Age-Dependent Developmental Changes of Selenium Content and Selenoprotein Expression and Content in Longissimus Dorsi Muscle and Liver of Duroc Pigs

The trace element selenium (Se) plays a key role in development and various physiological processes, mainly through its transformation into selenoproteins. To investigate the developmental patterns of Se content and expression of selenoproteins, the liver and longissimus dorsi (LD) muscle of Duroc pigs were collected at 1, 21, 80, and 185 days of age (7 pigs each age) for the determination of Se content, mRNA expression of selenoproteins, and concentrations of glutathione peroxidase (GPX), thioredoxin reductase (TrxR or TXNRD), and selenoprotein P (SELP). The results showed that age significantly affected the expression of GPX1, GPX2, GPX3, TXNRD1, TXNRD2, TXNRD3, iodothyronine deiodinases 2 (DIO2), DIO3, SELF, SELH, SELM, SELP, SELS, SELW, and selenophosphate synthetase2 (SPS2) in the liver, as well as GPX3, GPX4, TXNRD1, TXNRD2, DIO2, DIO3, SELF, SELN, SELP, SELR, SELS, and SELW in the LD muscle of Duroc pigs. The concentrations of GPX, TrxR, and SELP showed an increasing trend with age, and they were positively correlated with Se content at 1, 21, and 185 days of age and negatively correlated at 80 days of age, both in the liver and LD muscle. The Se content decreased at the age of 80 days, especially in the LD muscle. In summary, our study revealed developmental changes in Se content and expression of selenoproteins in the liver and LD muscle of Duroc pigs at different growth stages, which provided a theoretical basis for further study of Se nutrition and functions of selenoproteins.

Research Note: Effect of increasing fat supplementation in diets on productive performance, egg quality, and fatty liver incidence in laying hens throughout the entire laying cycle

This study aimed to investigate the effect of increasing fat supplementation in diets on productive performance, egg quality, and fatty liver incidence in laying hens during the entire laying cycle. A total of three hundred eighty-four 18-wk-old Hy-Line Brown laying hens were randomly allotted to 1 of 3 dietary treatments with 8 replicates for a 52-wk feeding trial. Each replicate comprised 16 consecutive cages with 1 hen per cage. The experimental diets were prepared by supplementing 0, 1.5, or 3.0% tallow to a basal diet, but all nutrients and energy in 3 diets were formulated to be equalized according to the recommended nutrient and energy concentrations at each phase of laying hens. Results indicated that increasing fat supplementation in diets decreased (linear, P < 0.01) feed conversion ratio (FCR) by increased egg mass (linear, P < 0.05) but decreased feed intake (linear and quadratic, P < 0.05) in laying hens during overall periods. Increasing fat supplementation in diets decreased (linear and quadratic, P < 0.05) egg yolk color during overall periods. Increasing fat supplementation in diets had no effects on liver color and hemorrhagic score measured at 60 wk (phase 3) and 70 wk of age (phase 4) without affecting hepatic fat concentrations during overall periods. However, the relative abdominal fat weight in laying hens was increased (linear and quadratic, P < 0.05) during overall periods by increasing fat supplementation in diets. In conclusion, increasing fat supplementation up to 3.0% in diets improves FCR with no impacts on fatty liver incidence and economics in laying hens throughout the entire laying cycle.

Effect of unconventional feeds on production cost, growth performance and expression of quantitative genes in growing pigs

This study examined the effects of unconventional feed on performance characteristics and candi-date gene expression in growing pigs of 3-5months of age. A Total of forty-five (45) growing pigs were randomly allotted into five treatments consisting of whole maize (T1), brewer’s dried grain (T2), cassava peel meal (T3), plantain peel meal (T4), and corn husk meal (T5), at 35% inclusion rate. Per-formance data were collected for 12weeks, while duodenum and liver samples were collected after the experiment for gene expression analysis. Data were analyzed in a completely randomized design. Diets significantly (p< 0.05) affected growth performance with treatment 2 recording the highest average daily weight gain of 0.21±0.02 whilecorn husk meal (T5)had the least 0.11±0.01. Feed efficiency was highest for whole maize (T1) and brewer’s dried grain (T2) (0.10±0.02) and lowest for t5 (0.07±0.17). Cost-benefit analysis were significantly different (p<0.05) with t4 recording the highest gross margin. Insulin-like growth factor1 and leptin gene were differentially expressed in tissues, while no significant differences (p>0.05) existed for growth hormone gene and ryanodine receptor1 gene. The results showed commendable gross margin, however, cognizance should be taken in the quantity of brewer’s dried grain fed to pigs since it increased the expression of ryanodine receptor 1 gene that leads to por-cine malignant hypertermia and pale soft exudates pork.

UPLC‐MS‐based plasma metabolomics for identifying energy metabolism biomarkers of maintenance in growing pigs

The purpose of this study is to explore the potential plasma metabolism biomarkers reflecting the maintenance status of growing pigs. The repeated measurement design was used in this experiment, and six barrows (28.6 ± 0.5 kg BW) were selected and kept in metabolism crates. The feeding level in growing pigs close to ad libitum was 2400 kJ ME/kg BW^0.6 ·day^-1 during Day 1 to Day 7, while a feeding level of 782 kJ ME/kg BW^0.6 ·day^-1 was provided as energy requirement for maintenance during Day 8 to Day 14. Plasma samples of each pig were collected from the anterior vena cava on the morning of Day 8 and Day 15. The metabolites of plasma were determined by high-resolution mass spectrometry using a metabolomics approach. Results showed that metabolomics analysis between ad libitum-fed state and maintained status revealed differences in 16 compounds. Identified compounds were enriched in metabolic pathways related to linoleic acid metabolism, tryptophan metabolism, and alanine, aspartate and glutamate metabolism. In conclusion, linoleic acid metabolism, tryptophan metabolism, alanine, aspartate and glutamic acid metabolism pathways played a major regulatory role in the maintenance status of growing pigs. The potential metabolism biomarkers of maintenance in growing pigs were linoleic acid, glutamine and tyrosine.

Application of Genetic, Genomic and Biological Pathways in Improvement of Swine Feed Efficiency

Despite the significant improvement of feed efficiency (FE) in pigs over the past decades, feed costs remain a major challenge for producers profitability. Improving FE is a top priority for the global swine industry. A deeper understanding of the biology underlying FE is crucial for making progress in genetic improvement of FE traits. This review comprehensively discusses the topics related to the FE in pigs including: measurements, genetics, genomics, biological pathways and the advanced technologies and methods involved in FE improvement. We first provide an update of heritability for different FE indicators and then characterize the correlations of FE traits with other economically important traits. Moreover, we present the quantitative trait loci (QTL) and possible candidate genes associated with FE in pigs and outline the most important biological pathways related to the FE traits in pigs. Finally, we present possible ways to improve FE in swine including the implementation of genomic selection, new technologies for measuring the FE traits, and the potential use of genome editing and omics technologies.

Increased feed supply and dietary fiber from sugar beet pulp improved energy retention in gestating sows

The aim of the study was to investigate whether increased inclusion of sugar beet pulp (SBP) alters retention of fat, protein, and energy when backfat (BF) is restored in early- and mid-gestation. In total, 46 sows were fed one of four treatments with increasing inclusion of SBP with dietary fiber (DF) levels of 119, 152, 185, and 217 g/kg; sows were assigned to one of three feeding strategies (FS; high, medium, and low) depending on BF thickness at mating and again at day 30 for the following month. On days 0, 30, 60, and 108, body weight (BW) and BF thickness were measured, and body pools of protein and fat were estimated using the deuterium technique. On days 30 and 60, urine, feces, and blood samples were collected to quantify metabolites, energy, and N balances. On days 15 and 45, heart rates were recorded to estimate the heat production. At farrowing, total born and weight of the litter were recorded. In early gestation, BW gain (P < 0.01) and body protein retention increased (P < 0.05) with increasing fiber inclusion, while body fat retention increased numerically by 59%. Increase in BF was the greatest for sows fed the high FS, intermediate when fed the medium strategy, and negligible for sows fed the lowest FS. N intake, N loss in feces, and N balance increased linearly, whereas N loss in urine tended to decrease with increasing inclusion of fibers in early gestation. Concomitantly, fecal energy output and energy lost as methane increased linearly (P < 0.001), while energy output in urine declined linearly, and total metabolizable energy intake, therefore, increased from 40.5 MJ ME/d in the low-fiber group to 43.5 mega joule (MJ) metabolizable energy (ME)/d in the high-fiber group (P < 0.001). Changing the metabolizable energy toward more ketogenic energy was expected to favor fat retention rather than protein retention. However, due to increased intake of metabolizable energy and increased N efficiency with increasing fiber inclusion, the sows gained more weight and protein with increasing fiber inclusion. In conclusion, increased feed intake improved both fat and protein retention, whereas increased DF concentration increased protein retention.

A regression for estimating metabolizable glucose in diets of weaned piglets for optimal growth performance

Objective

Two experiments were conducted to provide a new approach for evaluating feed nutritional value by metabolizable glucose (MG) in piglet diets with different levels of starch and crude fiber. In Exp 1, a regression equation for MG was generated. In Exp 2, the equation was verified, and the optimal growth performance of piglets under appropriate MG levels was tested.

Methods

In Exp 1, 20 weaned piglets (7.74±0.81 kg body weight [BW]) were randomly assigned to 1 of 4 treatments, including the basal diet containing different levels of MG (starch, 25.80%, 31.67%, 45.71%, 49.36%; crude fiber, 1.23%, 1.35%, 1.80%, 1.51%). The piglets were implanted with an ileal fistula, cannulation of the carotid artery, portal vein, and mesenteric artery. The chyme from the ileum fistula and blood samples were collected. In Exp 2, 30 weaned piglets (8.96±0.50 kg BW) were randomly assigned to 1 of 5 treatments, including the experimental diets with different levels of MG (37.6, 132.5, 300.0, 354.3, and 412.5 g/kg). The piglets’ BW, and feed consumption were recorded to calculate growth performance during the 28-d experiment.

Results

In Exp 1, the MG levels in 4 diets were 239.62, 280.68, 400.79, and 454.35 g/kg. The regression equation for the MG levels and dietary nutrients was: Y (MG) = 12.13×X₁ (starch)+23.18×X₂ (crude fiber)−196.44 (R² = 0.9989, p = 0.033). In Exp 2, treatments with 132.5 and 300.0 g/kg MG significantly (p<0.05) increased average daily gain and feed conversion efficiency of weaned piglets, increased digestibility of crude fat, and had no effect on digestibility of crude protein compared to 300.0 to 412.5 g/kg MG.

Conclusion

The pig model combining the ileum fistula and cannulation of blood vessels was successfully used to determine the dietary MG levels. The recommended MG level in weaned pig diets is 132.5 to 300.0 g/kg.

Fiber digestibility in growing pigs fed common fiber-rich ingredients: a systematic review

The application of high-fiber ingredients in the swine feed industry has some limitations considering that high amounts of fiber are resistant to endogenous enzymatic degradation in the pig’s gut. However, there is growing interest in fiber fermentation in the intestine of pigs due to their functional properties and potential health benefits. Many strategies have been applied in feed formulations to improve utilization efficiency of fiber-rich ingredients and stimulate their prebiotic effects in pigs. This manuscript reviews chemical compositions, physical properties, and digestibility of fiber-rich diets formulated with fibrous ingredients for growing pigs. Evidences presented in this review indicate there is a great variation in chemical compositions and physical properties of fibrous ingredients, resulting in the discrepancy of energy and fiber digestibility in pig intestine. In practice, fermentation capacity of fiber components in the pig’s intestine can be improved using strategies, such as biological enzymes supplementation and feed processing technologies. Soluble dietary fiber (SDF) and insoluble dietary fiber (IDF), rather than neutral detergent fiber (NDF) and acid detergent fiber (ADF), are recommended in application of pig production to achieve precise feeding. Limitations of current scientific research on determining fiber digestibility and short chain fatty acids (SCFA) production are discussed. Endogenous losses of fiber components from non-dietary materials that result in underestimation of fiber digestibility and SCFA production are discussed in this review. Overall, the purpose of our review is to provide a reference for feeding the pig by choosing the diets formulated with different high-fiber ingredients.

Effects of feeding corn distillers dried grains with solubles diets without or with supplemental enzymes on growth performance of pigs: a meta-analysis

A meta-analysis was conducted to determine the effects of the dietary energy system (net energy or metabolizable energy), oil content of corn distillers dried grains with solubles (cDDGS), diet inclusion levels, and pig age on growth performance of pigs fed cDDGS-based diets. Mean differences of average daily gain (ADG), average daily feed intake (ADFI), and gain:feed (G:F) were calculated and expressed as a percentage change relative to feeding corn-soybean meal (SBM)- and cDDGS-based diets to nursery [body weight (BW) < 25 kg] and growing-finishing (BW > 25 kg) pigs, and to compare the effects of supplementing various types of exogenous enzymes without or with phytase on growth performance. A total of 27 studies with 106 growth performance observations were included in the cDDGS dataset, and 34 studies with 84 observations for enzyme responses in cDDGS diets were used in the enzyme dataset. Approximately, 64.7% of the observations showed no change, and 26.7% of observations showed a reduction in ADG, ADFI, and G:F when feeding cDDGS-based diets to the nursery and growing-finishing pigs compared with feeding corn-SBM-based diets. Furthermore, feeding cDDGS diets resulted in decreased (P < 0.01) mean difference of ADG (-4.27%) and G:F (-1.99%) for nursery pigs, and decreased (P < 0.01) mean difference of ADG (-1.68%) and G:F (-1.06%) for growing-finishing pigs. Every percentage unit increase in the inclusion level of cDDGS in growing-finishing pig diet was associated with a decrease (P < 0.01) in ADG (-0.10%) and ADFI (-0.09%). Feeding high oil (≥10% ether extract) cDDGS-based diets to pigs resulted in a 2.96% reduction in ADFI whereas feeding reduced-oil (<10% ether extract) cDDGS-based diets reduced G:F by 1.56% compared with pigs fed corn-SBM-based diets. Supplementation of exogenous enzymes improved (P < 0.05) the mean difference of ADG and G:F by 1.94% and 2.65%, respectively, in corn-SBM-based diets, and by 2.67% and 1.87%, respectively, in cDDGS diets. Supplementation of exogenous protease, enzyme cocktail, or xylanase improved (P < 0.05) ADG by 7.29%, 2.64%, and 2.48% in pigs fed corn-SBM-based diets, respectively. There were no differences between the dietary addition of single enzymes and enzyme combinations for any growth performance parameters in corn-SBM- or cDDGS-based diets. In conclusion, feeding cDDGS-based diets slightly reduces the growth performance of nursery and growing-finishing pigs, but supplementation of xylanase or enzyme cocktail can improve G:F of pigs fed cDDGS-based diets.

Measures Matter-Determining the True Nutri-Physiological Value of Feed Ingredients for Swine

Many types of feed ingredients are used to provide energy and nutrients to meet the nutritional requirements of swine. However, the analytical methods and measures used to determine the true nutritional and physiological ("nutri-physiological") value of feed ingredients affect the accuracy of predicting and achieving desired animal responses. Some chemical characteristics of feed ingredients are detrimental to pig health and performance, while functional components in other ingredients provide beneficial health effects beyond their nutritional value when included in complete swine diets. Traditional analytical procedures and measures are useful for determining energy and nutrient digestibility of feed ingredients, but do not adequately assess their true physiological or biological value. Prediction equations, along with ex vivo and in vitro methods, provide some benefits for assessing the nutri-physiological value of feed ingredients compared with in vivo determinations, but they also have some limitations. Determining the digestion kinetics of the different chemical components of feed ingredients, understanding how circadian rhythms affect feeding behavior and the gastrointestinal microbiome of pigs, and accounting for the functional properties of many feed ingredients in diet formulation are the emerging innovations that will facilitate improvements in precision swine nutrition and environmental sustainability in global pork-production systems.

Evaluation of energy values of high-fiber dietary ingredients with different solubility fed to growing pigs using the difference and regression methods

The objective of this study was to compare the energy values of high-fiber dietary ingredients with different solubility (sugar beet pulp [SBP] and defatted rice bran [DFRB]) in growing pigs using the difference and the regression methods. A total of 21 barrows (initial BW, 40.5 ± 1.2 kg) were assigned to 3 blocks with BW as a blocking factor, and each block was assigned to a 7 × 2 incomplete Latin square design with 7 diets and two 13-d experimental periods. The 7 experimental diets consisted of a corn-soybean meal basal diet and 6 additional diets containing 10%, 20%, or 30% SBP or DFRB in the basal diet, respectively. Each of the experimental periods lasted 12 d, with a 7 d dietary adaptation period followed by 5-d total fecal and urine collection. Results showed that the digestible energy (DE) and metabolizable energy (ME) of the SBP determined by the difference method with different inclusion levels (10%, 20%, or 30%) were 2,712 and 2,628 kcal/kg, 2,683 and 2,580 kcal/kg, and 2,643 and 2,554 kcal/kg DM basis, respectively. The DE and ME in the DFRB evaluated by the difference method with 3 different inclusion levels were 2,407 and 2,243 kcal/kg, 2,687 and 2,598 kcal/kg, and 2,630 and 2,544 kcal/kg DM basis, respectively. Different inclusion levels had no effects on the energy values of each test ingredient estimated by the difference method. The DE and ME of the SBP and the DFRB estimated by the regression method were 2,562 and 2,472 kcal/kg and 2,685 and 2,606 kcal/kg DM basis, respectively. The energy values of each ingredient determined by the regression method were similar to the values estimated by the difference method with the 20% or 30% inclusion level. However, the energy values of the SBP and DFRB estimated by the difference method with the 10% inclusion level were inconsistent with the values determined by the regression method (P < 0.05). In conclusion, the regression method was a robust indirect method to evaluate the energy values for high-fiber ingredients with different solubility in growing pigs. If the number of experimental animals was limited, the difference method with a moderate inclusion level (at least 20%) of the test high-fiber ingredient in the basal diet could be applied to substitute the regression method.

Assessment of milk yield and nursing calf feed intake equations in predicting calf feed intake and weaning weight among breeds

Nutrition models are important tools in management decisions, but improvements are needed for cow-calf producers to accurately predict nursing calf performance. Therefore, the objective of this study was to assess the ability of published milk yield (MY) and forage intake equations to predict calf feed intake and weaning weight (WW) using an independent, multi-breed dataset. A dataset with 406 nursing calves was used to evaluate two MY equations: 1) National Academies of Sciences, Engineering, and Medicine (2016) (NASEM) and 2) Wood (1967) (WOOD) and five feed intake equations: 1) equations from Table 9.1 in Tedeschi et al. (2006) (TED06), 2) equations 2 to 7 in Baker et al. (1976) (BAK76), 3) equation 25 in Tedeschi and Fox (2009) (TED09A), 4) equations 17, 19, and 24 in Tedeschi and Fox (2009) (TED09B), and 5) equation from Holloway et al. (1982) (HOL82). MY was measured at 14-d interval by hand milking, and individual feed intake of nursing calves was determined during a 240-d nursing period. Calf birth and WW were measured on days 0 and 240, respectively. Each combination of MY and feed intake equation was used to predict calf feed intake and WW from observed MY, calf birth weight, and calf slaughter weight. Predicted and observed values were compared using concordance correlation coefficient (CCC) and mean bias (MB). Factors affecting the deviation between observed and predicted values were analyzed using regression, and a revised equation was developed. Feed intake equations poorly predicted observed feed intake with CCC < 0.4 and MB ranged from -108% to 69%. However, statistics were slightly improved when using WOOD rather than the NASEM MY equation. BAK76 and TED09B feed intake equations were considerably more accurate (MB = -14.4% to 13.0%) in predicting feed intake but still not precise (CCC < 0.30). Predictions of WW had CCC ranging from 0.19 to 0.71 and MB ranging from -25.9% to 41.8% and were not significantly affected by the MY equation. TED06 and BAK76 feed intake equations were the most precise (CCC > 0.60) and accurate (MB = 1.7% to 8.5%) in predicting WW. Sire breed accounted for significant variation in the deviation between observed and predicted values of feed intake and in a revised equation to predict total feed energy intake from total milk energy intake. In conclusion, refinements of feed intake equations for nursing calves need to account for breed to improve current nutrition models.

Prediction equations for digestible and metabolizable energy concentrations in feed ingredients and diets for pigs based on chemical composition

OBJECTIVE

The objectives were to develop prediction equations for digestible energy (DE) and metabolizable energy (ME) of feed ingredients and diets for pigs based on chemical composition and to evaluate the accuracy of the equations using in vivo data.

METHODS

A total of 734 data points from 81 experiments were employed to develop prediction equations for DE and ME in feed ingredients and diets. The CORR procedure of SAS was used to determine correlation coefficients between chemical components and energy concentrations and the REG procedure was used to generate prediction equations. Developed equations were tested for the accuracy according to the regression analysis using in vivo data.

RESULTS

The DE and ME in feed ingredients and diets were most negatively correlated with acid detergent fiber or neutral detergent fiber (NDF; r = -0.46 to r = -0.67; p<0.05). Three prediction equations for feed ingredients reflected in vivo data well as follows: DE = 728+0.76×gross energy (GE)-25.18×NDF (R2 = 0.64); ME = 965+0.66×GE-24.62×NDF (R2 = 0.60); ME = 1,133+0.65×GE-29.05×ash-23.17×NDF (R2 = 0.67).

CONCLUSION

In conclusion, the equations suggested in the current study would predict energy concentration in feed ingredients and diets.

Protein and energy concentrations of meat meal and meat and bone meal fed to pigs based on in vitro assays

The objective of this study was to develop equations for estimating ileal digestible crude protein (CP) and metabolizable energy (ME) contents of meat meal (MM) and meat and bone meal (MBM) as feed ingredients for pigs based on in vitro assays. Test ingredients were 4 sources of MM and 3 sources of MBM. Ash and CP contents of the ingredients ranged from 3.8% to 33.1% and 46.8% to 82.9% (as-is basis), respectively. In vitro ileal disappearance (IVID) of CP was determined and ileal digestible CP content was calculated by multiplying CP content by IVID of CP. In vitro total tract disappearance (IVTTD) of dry matter (DM) was determined and ME was calculated using gross energy, CP contents, and IVTTD of DM. The IVID of CP and IVTTD of DM ranged from 77.2% to 88.7% and from 82.7% to 92.4%, respectively. Calculated ileal digestible CP and ME contents ranged from 37.8% to 73.5% DM and 2,405 to 3,905 kcal/kg DM, respectively. Ash contents were negatively correlated (P < 0.001) with CP (r = −0.99), in vitro ileal digestible CP (r = −0.97), gross energy (r = −1.00), in vitro digestible energy (r = −0.97), and adjusted ME (r = −0.97). The most fitting equations for ileal digestible CP and adjusted ME were: ileal digestible CP (% DM) = 11.91 − 0.90 × Ash (% DM) + 0.74 × IVID of CP (%) (R² = 0.99) and adjusted ME (kcal/kg DM) = 130.85 − 50.90 × ash (% DM) + 47.06 × IVTTD of DM (%) (R² = 0.99). To validate the accuracy of the prediction equations for ME, mean bias and linear bias were determined using a regression analysis. Calculated ME values of MM and MBM were in a good agreement with data obtained from animal experiments based on a statistically insignificant bias in the models. In conclusion, ME concentrations of MM and MBM as swine feed ingredients can be calculated using ash concentration and in vitro disappearance of dry matter.

Colonic microbiome profiles for improved feed efficiency can be identified despite major effects of farm of origin and contemporary group in pigs

While feed efficiency (FE) is a trait of great economic importance to the pig industry, the influence of the intestinal microbiome in determining FE is not well understood. The objective of this experiment was to determine the relative influence of FE and farm of birth on the pig colonic microbiome. Animals divergent in residual feed intake (RFI) were sourced from two geographically distinct locations (farms A + B) in Ireland. The 8 most efficient (low RFI (LRFI)) and 8 least efficient (high RFI, (HRFI)) pigs from farm A and 12 LRFI and 12 HRFI pigs from farm B were sacrificed. Colonic digesta was collected for microbial analysis using 16S ribosomal RNA gene sequencing and also for volatile fatty acid analysis. The α-diversity differed between the farms in this study, with pigs from farm A having greater diversity based on Shannon and InvSimpson measures compared to pigs from farm B (P < 0.05), with no difference identified in either Chao1 or observed measures of diversity (P > 0.05). In the analysis of β-diversity, pigs clustered based on farm of birth rather than RFI. Variation in the management of piglets, weight of the piglets, season of the year, sanitary status and dam dietary influence could potentially be causative factors in this large variation between farms. However, despite significant variation in the microbial profile between farms, consistent taxonomic differences were identified between RFI groups. Within the phylum Bacteroidetes, the LRFI pigs had increased abundance of BS11 (P < 0.05) and a tendency toward increased Bacteroidaceae (P < 0.10) relative to the HRFI group. At genus level, the LRFI pigs had increased abundance of Colinsella (P < 0.05), a tendency toward increased Bacteroides and CF231 (P < 0.10). At species level, Ruminococcus flavefaciens had increased abundance in the LRFI compared to the HRFI animals. In conclusion, while farm of birth has a substantial influence on microbial diversity in the pig colon, a microbial signature indicative of FE status was apparent.

Increasing Dietary Lysine Impacts Differently Growth Performance of Growing Pigs Sorted by Body Weight

An experiment was conducted analyzing whether growing pigs classified in different initial body weight categories (BWCAT) have a different response to increasing standardized ileal digestible lysine to net energy ratio (SID Lys:NE), to assess whether light pigs might benefit from being differentially fed. A total of 1170 pigs in pens of 13 were individually weighed, classified in 3 BWCAT (Lp: 32.1 ± 2.8 kg, Mp: 27.5 ± 2.3 kg, and Sp: 23.4 ± 2.9 kg), and afterwards pens were randomly allocated to 5 dietary SID Lys:NE treatments (3.25 to 4.88 g/Mcal) fed over 47 days. Results reported a greater linear improvement of growth and feed efficiency of Sp compared to Lp when increasing SID Lys:NE. Modelling the response to SID Lys:NE using quadratic polynomial models showed that the levels to reach 98% of maximum growth from day 0-47 were 3.67, 3.88, 4.06 g SID Lys/Mcal NE for Lp, Mp, and Sp, respectively. However, due to the overlapping SID Lys:NE confidence intervals at maximum performance, it was not possible to determine if requirements were different between BWCAT. Summarizing, the results suggested that feeding small pigs greater SID Lys:NE than large pigs can improve their performance and increase the efficiency of the overall production system.

Effects of a Hatchery Byproduct Mixture on Growth Performance and Digestible Energy of Various Hatchery Byproduct Mixtures in Nursery Pigs

The objectives were to determine effects of a hatchery byproduct mixture (HBM) on growth performance and to measure digestible energy concentrations in various HBM. In the growth performance experiment, 96 pigs (initial body weight = 9.6 ± 0.8 kg) were assigned to 4 dietary treatments in a randomized complete block design with 6 blocks. Each treatment consisted of 6 replicate pens with 4 pigs comprising 2 barrows and 2 gilts. Pigs were fed graded concentrations of HBM at 0%, 3.33%, 6.67%, and 10.00% for 14 days. In the energy digestibility experiment, 10 barrows (initial body weight = 11.5 ± 0.4 kg) were employed to determine digestible energy in HBM. A basal diet based on corn and soybean meal and 4 additional diets containing 25% of 4 different HBM were prepared. The marker-to-marker method was employed for total collection and the experimental design was a replicated 5 × 4 Latins square design. Growth performance was not compromised as the inclusion rate of HBM increased up to 10%. Digestible energy of HBM ranged from 2772 to 3887 kcal/kg as-is basis. In conclusion, HBM can be used in nursery pig diets and different energy values should be used for each HBM.

Meat quality from pigs fed tomato processing waste

Sixteen Nero Siciliano pigs were used to investigate the effect of dietary tomato processing waste on meat quality. During 86 days one group (CON, n = 8) received a pelleted conventional diet, while another group (TOM, n = 8) received the same diet in which tomato waste replaced 15% of corn. The dietary treatment did not affect growth performances. The TOM diet reduced intramuscular fat, SFA and MUFA content, while increasing the n-6:n-3 ratio in meat (P < .05). The TOM diet increased the concentration of PUFA, PUFA n-3, PUFA n-6 and the n-6:n-3 ratio (P < .01). The instrumental colour descriptors of backfat were unaffected by diet. The TOM diet increased deposition of retinol in meat (P < .001) but did not affect oxidative stability parameters measured in fresh meat and meat homogenates with pro-oxidant catalysts. Concluding, tomato pomace fed to pigs at higher levels compared to previous reports had no adverse effects on the investigated meat quality traits.

Analysis of the basal colonic innate immune response of pigs divergent in feed efficiency and following an ex vivo lipopolysaccharide challenge

While feed efficiency is influenced by multiple physiological processes, it is not known how efficient and inefficient pigs differ in relation to their basal immune response, and particularly their innate immune response to a microbial challenge. Hence, the objective was to examine the expression of genes encoding innate immune response markers in basal colonic tissue and colonic tissue following an ex vivo lipopolysaccharide (LPS) challenge from pigs divergent in residual feed intake (RFI). Pigs that differed in RFI were selected from two different farms of origin. Colonic tissue was harvested from high RFI (HRFI) and low (LRFI) pigs, and two experimental conditions were explored: the first was basal unchallenged tissue and the second was colonic tissue following an ex vivo LPS challenge. RNA was extracted and tested on a Nanostring panel of 72 genes coding for barrier defense proteins, transmembrane receptors, kinases, transcription regulators, cytokines, and cytokine regulators. In the basal unchallenged tissue, the LRFI pigs had increased expression of AOAH, AP1, and TRAM and the cytokines TNF, IL10, and CXCL8, compared with the HRFI pigs (P < 0.05), with a significant effect of farm of origin on 31 genes (P < 0.05). In the LPS-challenged tissues, the LRFI group had higher expression of TLR1, TLR7, TLR8, GPR43/FFAR2, JAK2, and NFAM1 compared with the HRFI group (P < 0.05). In conclusion, these data suggest that LRFI pigs have an upregulated basal colonic inflammatory state and a heightened response to an LPS challenge compared with the inefficient HRFI pigs. This immune profile potentially enhances their capacity to respond to an infectious challenge.

A comparative analysis of the transcriptome profiles of liver and muscle tissue in pigs divergent for feed efficiency

BACKGROUND

The improvement of feed efficiency is a key economic goal within the pig production industry. The objective of this study was to examine transcriptomic differences in both the liver and muscle of pigs divergent for feed efficiency, thus improving our understanding of the molecular mechanisms influencing feed efficiency and enabling the identification of candidate biomarkers. Residual feed intake (RFI) was calculated for two populations of pigs from two different farms of origin/genotype. The 6 most efficient (LRFI) and 6 least efficient (HRFI) animals from each population were selected for further analysis of Longissimus Dorsi muscle (n = 22) and liver (n = 23). Transcriptomic data were generated from liver and muscle collected post-slaughter.

RESULTS

The transcriptomic data segregated based on the RFI value of the pig rather than genotype/farm of origin. A total of 6463 genes were identified as being differentially expressed (DE) in muscle, while 964 genes were identified as being DE in liver. Genes that were commonly DE between muscle and liver (n = 526) were used for the multi-tissue analysis. These 526 genes were associated with protein targeting to membrane, extracellular matrix organisation and immune function. In the muscle-only analysis, genes associated with RNA processing, protein synthesis and energy metabolism were down regulated in the LRFI animals while in the liver-only analysis, genes associated with cell signalling and lipid homeostasis were up regulated in the LRFI animals.

CONCLUSIONS

Differences in the transcriptome segregated on pig RFI value rather than the genotype/farm of origin. Multi-tissue analysis identified that genes associated with GO terms protein targeting to membrane, extracellular matrix organisation and a range of terms relating to immune function were over represented in the differentially expressed genes of both liver and muscle.

Effect of different sources and inclusion levels of dietary fat on productive performance and egg quality in laying hens raised under hot environmental conditions

Objective

This experiment aimed to investigate the effect of different sources and inclusion levels of dietary fat on productive performance and egg quality in laying hens raised under hot environmental conditions.

Method

A total of 480 Hy-Line Brown laying hens at 31 wk of age were randomly allotted to 1 of 5 experimental diets. The control diet contained 2,800 kcal/kg AMEn with no fat addition. Four additional diets were prepared by adding 2.0 or 4.0% of animal fat (AF) or soybean oil (SO). Energy and nutrient concentrations were consistent among all diets. Diets were fed to hens for 4 weeks. Average daily room temperature and humidity were 26.7 ± 1.52°C and 77.4 ± 4.50%. The heat stress index was approximately 76, indicating that hens were raised under heat stress conditions.

Results

Final BW was greater (p<0.05) for hens fed diets containing 2.0 or 4.0% AF than for those fed the control diet or diets containing 2.0 or 4.0% SO. The BW gain and feed intake were greater (p<0.05) for hens fed diets containing additional AF or SO than those fed the control diet. Eggshell thickness were the greatest (p<0.05) for hens fed the control diet, but the least (p<0.05) for hens fed diets containing 4.0% SO. Egg yolk color was the greatest (p<0.05) for hens fed to the control diet, but the least (p<0.05) for hens fed diets containing 4.0% SO.

Conclusion

Inclusion of supplemental fat (AF and SO) in diets exhibits preventative effects on BW loss for hens raised under hot environmental conditions when energy and nutrient concentrations in diets were maintained. The effects were greater for AF than for SO. However, inclusion of supplemental fat in diets decreases eggshell thickness and egg yolk yellowness, possibly due to a reduction in Ca absorption and intake of egg yolk colorants.

Energy, amino acid, and phosphorus digestibility and energy prediction of thermally processed food waste sources for swine

Recycling energy and nutrients from food waste into animal feed decreases the environmental impact of food animal production. However, recycling energy and nutrients from various food waste sources into swine feeding programs is constrained by the high variability and lack of data on the digestibility of energy and nutrients. Therefore, the objectives of this study were to evaluate the digestibility of energy, amino acids, and phosphorus in thermally dried food waste sources fed to growing pigs and to compare in vivo determined digestibility values with those obtained from in vitro digestibility procedures and published prediction equations to determine the accuracy of using these nutritional evaluation methods. Pigs (n = 36; initial body weight = 16.37 ± 1.9 kg) were utilized to determine digestible energy (DE) and metabolizable energy (ME) content, as well as standardized total tract digestibility (STTD) of phosphorus and standardized ileal digestibility (SID) of amino acids in three sources of dehydrated food waste in three separate trials. Initial body weight of pigs at the beginning of each digestibility trial was used as the blocking factor in a randomized complete block design. Diets were formulated to contain 30% food waste derived from fish waste (FW), supermarket waste (containing bakery, fruits and vegetables, meat, and deli foods from a single supermarket; SMW), and fruit and vegetable waste (FVW). The DE and ME content of FW (DE = 5,057 kcal/kg; ME = 4,820 kcal/kg) and SMW (DE = 5,071 kcal/kg; ME = 4,922 kcal/kg) were not different (P > 0.05), whereas FVW had the least (P < 0.05) DE (2,570 kcal/kg) and ME (2,460 kcal/kg) content compared with FW and SMW. Digestibility of crude protein and amino acids was greater (P < 0.05) in FW and SMW compared with FVW. The in vitro digestibility procedure can be used to approximate the digestibility of dry matter (DM) and energy in SMW, FW, and FVW compared with in vivo estimates, but significant error exists depending on the chemical characteristics of each food waste source. However, use of the prediction equations and digestibility data obtained from the in vitro procedure resulted in high accuracy in estimating DE content of FW (observed = 5,058 kcal/kg DM vs. predicted = 4,948 kcal/kg DM), SMW (observed = 5,071 kcal/kg DM vs. predicted 4,978 kcal/kg DM), and FVW (observed = 2,570 kcal/kg DM vs. predicted 2,814 kcal/kg DM) sources.

Metabolizable energy requirement for maintenance estimated by regression analysis of body weight gain or metabolizable energy intake in growing pigs

Objective

Feed energy required for pigs is first prioritized to meet maintenance costs. Additional energy intake in excess of the energy requirement for maintenance is retained as protein and fat in the body, leading to weight gain. The objective of this study was to estimate the metabolizable energy requirements for maintenance (ME_m) by regressing body weight (BW) gain against metabolizable energy intake (MEI) in growing pigs.

Methods

Thirty-six growing pigs (26.3±1.7 kg) were allotted to 1 of 6 treatments with 6 replicates per treatment in a randomized complete block design. Treatments were 6 feeding levels which were calculated as 50%, 60%, 70%, 80%, 90%, or 100% of the estimated ad libitum MEI (2,400 kJ/kg BW^0.60 d). All pigs were individually housed in metabolism crates for 30 d and weighed every 5 d. Moreover, each pig from each treatment was placed in the open-circuit respiration chambers to measure heat production (HP) and energy retained as protein (RE_p) and fat (RE_f) every 5 d. Serum biochemical parameters of pigs were analyzed at the end of the experiment.

Results

The average daily gain (ADG) and HP as well as the RE_p and RE_f linearly increased with increasing feed intake (p<0.010). β-hydroxybutyrate concentration of serum tended to increase with increasing feed intake (p = 0.080). The regression equations of MEI on ADG were MEI, kJ/kg BW^0.60 d = 1.88×ADG, g/d+782 (R² = 0.86) and ME_m was estimated at 782 kJ/kg BW^0.60 d. Protein retention of growing pigs would be positive while RE_f would be negative at this feeding level via regression equations of RE_p and RE_f on MEI.

Conclusion

The ME_m was estimated at 782 kJ/kg BW^0.60 d in current experiment. Furthermore, growing pigs will deposit protein and oxidize fat if provided feed at the estimated maintenance level.

Effect of different time intervals after feeding on plasma metabolites in growing pigs: an UPLC-MS-based metabolomics study

A diet consumed by pigs provides the nutrients for the production of a large number of metabolites that, after first-pass metabolism in the liver, circulate systemically where they may exert diverse physiologic influences on pigs. So far, little is known of how feeding elicits changes in metabolic profiles for growing pigs. This study investigated differences in plasma metabolites in growing pigs at several intervals after feeding using the technique of metabolomics. Ten barrows (22.5 ± 0.5 kg BW) were fed a corn-soybean meal basal diet and were kept in metabolism crates for a period of 11 days. An indwelling catheter was inserted into the jugular vein of each pig before the experimental period. Plasmas before and 1, 4, and 8 hr after feeding were collected at day 11 and differential metabolites were determined using a metabolomics approach. Direct comparison at several intervals after feeding revealed differences in 14 compounds. Identified signatures were enriched in metabolic pathways related to linoleic acid metabolism, arginine and proline metabolism, lysine degradation, glycine, serine and threonine metabolism, and lysine biosynthesis. These results suggest that plasma metabolites of growing pigs after feeding were modulated through changes in linoleic acid metabolism and amino acid metabolism.

Effect of dietary fiber content on nutrient digestibility and fecal microbiota composition in growing-finishing pigs

Microbial population in the gastrointestinal tract plays a central role in health and nutrient digestion. The objective of the present study was to investigate the relationships between microbiota and apparent digestibility coefficients with respect to age and diet. Pigs from Large-White, Duroc or Pietrain breeds were raised under the same housing conditions and fed alternately a low-fiber (LF) and a high-fiber diet (HF) during 4 successive 3-week periods. Data collection for digestibility measurements was achieved during the last week of each period. At the end of each period, fecal microbiota was collected for 16S rRNA gene sequencing. The microbiota remained stable across periods whereas digestibility of energy, crude proteins and cell wall components increased. The microbiota was resilient to diet effect and pigs fed the LF diet were discriminated to those fed the HF diet using 31 predicting OTUs with a mean classification error-rate of 3.9%. Clostridiaceae and Turicibacter were negatively correlated whereas Lactobacillus was positively correlated with protein and energy digestibility coefficients in the LF group. In addition, Lachnospiraceae and Prevotella were negatively correlated with cell wall component digestibility. In contrast, no significant correlation was found between microbiota composition and digestibility coefficients when pigs were fed the HF diet. Interestingly, it was also no longer possible to distinguish animals from different breeds once the animals were fed a HF diet, so that the microbiota could only trace the breed origin in the first period and in the LF group. In our experimental conditions, 3 weeks of adaptation to a new diet seems to be sufficient to observe resilience in growing pigs’ microbiota. We demonstrated that fecal microbiota can be used to classify pigs according to their dietary treatment. Some bacteria are favorable or unfavorable to digestibility. This suggests that manipulations of bacterial populations can improve digestibility and feed efficiency.

Estimated energy and nutrient composition of different sources of food waste and their potential for use in sustainable swine feeding programs

About 40% of the total food produced in the United States is wasted throughout the supply chain. The objective of this study was to determine the energy and nutrient content and variability of food waste sources generated at different stages within the food supply chain in the Minneapolis–St. Paul, MN, metropolitan area, and their potential for use in swine diets. A total of four waste sources were selected: supermarket (SM; retail to consumer), university residential dining hall (RH; consumer to postconsumer), a city waste transfer station (TS; postconsumer to municipal waste disposal), and household source-separated organic recycling program (SSO; postconsumer to municipal waste). Samples were collected (SM: n = 22; RH: n = 60; TS: n = 27; SSO: n =12) and analyzed for GE, proximate analyses, minerals, amino acids, and fatty acid concentrations along with lipid peroxidation indicators including peroxide value (PV) and thiobarbituric reactive substances (TBARS). Data were analyzed using a general linear model that included food waste source as the main factor, and least squared means with adjustment were used for multiple comparisons. Samples of SM food waste contained the greatest (P < 0.05) concentration of GE (5,909 kcal/kg) compared with RH, TS, and SSO sources. Calculated NE of SM (3,740 kcal/kg) was also the greatest compared with the three other food waste sources. Food waste from SM, RH, and SSO, but not TS, had greater (P < 0.05) calculated NE than published values for corn and soybean meal. Concentrations of Lys (1.82%), Met (0.53%), Thr (1.07%), and Trp (0.27) content were greater in SM than in RH, TS, and SSO, but these concentrations were less than published values for soybean meal. There were no differences (P > 0.05) in the phosphorus content of samples among food waste sources (0.30% to 0.64%). PV and TBARS were greatest (P < 0.05) in the SSO samples (PV = 82.4 meq/kg oil; TBARS = 2.44 mg malondialdehyde (MDA) eq/g oil) compared with the other three food waste sources. Although the concentrations of nutrients and calculated energy values of the food waste sources were moderately high compared with corn and soybean meal, their composition was more variable (i.e., greater SD of means). Food waste generated upstream (SM) in the food supply chain appears to have greater nutritional value than postconsumer food waste (RH, TS, and SSO), but all sources appear suitable for use in commercial swine diets provided that ME, NE, and nutrient digestibility values are well characterized.

Methodologies on estimating the energy requirements for maintenance and determining the net energy contents of feed ingredients in swine: a review of recent work

In the past two decades, a considerable amount of research has focused on the determination of the digestible (DE) and metabolizable energy (ME) contents of feed ingredients fed to swine. Compared with the DE and ME systems, the net energy (NE) system is assumed to be the most accurate estimate of the energy actually available to the animal. However, published data pertaining to the measured NE content of ingredients fed to growing pigs are limited. Therefore, the Feed Data Group at the Ministry of Agricultural Feed Industry Centre (MAFIC) located at China Agricultural University has evaluated the NE content of many ingredients using indirect calorimetry. The present review summarizes the NE research works conducted at MAFIC and compares these results with those from other research groups on methodological aspect. These research projects mainly focus on estimating the energy requirements for maintenance and its impact on the determination, prediction, and validation of the NE content of several ingredients fed to swine. The estimation of maintenance energy is affected by methodology, growth stage, and previous feeding level. The fasting heat production method and the curvilinear regression method were used in MAFIC to estimate the NE requirement for maintenance. The NE contents of different feedstuffs were determined using indirect calorimetry through standard experimental procedure in MAFIC. Previously generated NE equations can also be used to predict NE in situations where calorimeters are not available. Although popular, the caloric efficiency is not a generally accepted method to validate the energy content of individual feedstuffs. In the future, more accurate and dynamic NE prediction equations aiming at specific ingredients should be established, and more practical validation approaches need to be developed.

Prediction of digestible and metabolizable energy of corn distillers dried grains with solubles for growing pigs using in vitro digestible nutrients

The objective of this study was to develop prediction equations (EQS) that estimate DE and ME content of corn distillers dried grains with solubles (DDGS) using digestible (DIG) nutrients from in vitro or in vivo assays. Chemical composition data from 12 sources of corn DDGS were obtained using laboratory chemical analysis (LCA) and near infrared spectroscopy (NIRS). In vitro DM disappearance (IVDMD) from gastric and small intestine hydrolysis (IVDMDh), large intestine fermentation (IVDMDf), and total tract digestion (IVDMDt) were also determined along with in vivo apparent total tract digestibility (ATTD) of DM, CP, ether extract (EE), NDF, and ADF, and energy values (GE, DE, and ME). Correlation analysis was used to compare chemical composition from LCA with NIRS, and a stepwise selection of variables was performed using linear regression to establish DE and ME prediction EQS. Composition determined by NIRS did not correlate with values from LCA. Consequently, significance and R2 were poorer when using NIRS data as inputs to predict DE (P = 0.11; R2 = 0.23) and ME (P = 0.11; R2 = 0.24). However, when using LCA data, DE (P = 0.04; R2 = 0.35) and ME (P = 0.04; R2 = 0.52) estimates of corn DDGS obtained from prediction EQS had significant P values, but low R2. Better prediction of DE (P < 0.01; R2 = 0.83) and ME (P < 0.01; R2 = 0.76) was observed when using in vivo DIG nutrients as inputs (DM basis) for DE, kcal/kg = 854.5 + (3.6 × DIG DM, g/kg) + (3.7 × DIG EE, g/kg) + (2.0 × DIG NDF, g/kg) and ME, kcal/kg = 704.5 + (3.3 × DIG DM, g/kg) + (4.8 × DIG EE, g/kg) + (2.6 × DIG NDF, g/kg). In vitro DIG DM, but not in vitro DIG NDF, was selected for use in EQS (7) DE, kcal/kg = 6,383.6 - (42.5 × in vitro DIG DM, g/kg) + (35.4 × DIG EE, g/kg) and (8) ME, kcal/kg = 6,635.1 - (49.8 × in vitro DIG DM, g/kg) + (41.3 × DIG EE, g/kg), but the significance and accuracy for both DE (P = 0.07; R2 = 0.45) and ME (P = 0.05; R2 = 0.49) predictions was less using in vitro DIG nutrient values than using in vivo DIG nutrient values. If chemical composition was used to replace in vivo EE, along with in vitro DIG NDF and DM, the prediction EQS only used the concentration of ADF and EE as predictors instead of in vitro DIG NDF and DM. In conclusion, in vivo DIG NDF, DM, and EE are the best predictors for DE and ME content of corn DDGS for swine. Using NIRS to determine chemical composition, in vitro DIG NDF, and in vitro DIG DM did not result in accurate predictions of DE and ME.

Effects of dietary β-mannanase supplementation on the additivity of true metabolizable energy values for broiler diets

Objective

This experiment was conducted to determine the effects of dietary β-mannanase on the additivity of true metabolizable energy (TME) and nitrogen-corrected true metabolizable energy (TME_n) for broiler diets.

Methods

A total of 144 21-day-old broilers were randomly allotted to 12 dietary treatments with 6 replicates. Five treatments consisted of 5 ingredients of corn, wheat, soybean meal, corn distillers dried grains with solubles, or corn gluten meal. One mixed diet containing 200 g/kg of those 5 ingredients also was prepared. Additional 6 treatments were prepared by mixing 0.5 g/kg dietary β-mannanase with those 5 ingredients and the mixed diet. Based on a precision-fed chicken assay, TME and TME_n values for 5 ingredients and the mixed diet as affected by dietary β-mannanase were determined.

Results

Results indicated that when β-mannanase was not added to the diet, measured TME and TME_n values for the diet did not differ from the predicted values for the diet, which validated the additivity. However, for the diet containing β-mannanase, measured TME_n value was greater (p<0.05) than predicted TME_n value, indicating that the additivity was not validated.

Conclusion

In conclusion, the additivity of energy values for the mixed diet may not be guaranteed if the diet contains β-mannanase.

Predicting the nutritional quality of feed ingredients for pigs using near-infrared spectroscopy (NIRS) and chemical analysis

Capacity to routinely, accurately and cost-effectively measure variation in the nutritional quality of feed ingredients before diet formulation represents a fundamental pillar of sustainable pork production worldwide. Factors driving sustainable pork production include pork price, feed cost, utilisation of co-products and downgraded raw materials and variation in pork production, with all being related to the definition and ultimate nutritional quality of feed ingredients. The present paper defines rapid measures of nutritional quality in feed ingredients for pigs and demonstrates the range that can exist in these parameters, specifically digestible energy of cereal grains and the reactive-lysine concentration of oilseed meals. It provides an overview of the development of near-infrared spectroscopy (NIRS) calibrations for key nutritional-quality parameters and how they are being applied by the pork industry. Adjunct ways to measure nutritional quality of feed ingredients for pigs such as the glucose-release index and how these can be used in conjunction with NIRS are reviewed. The paper reports advanced correlation analysis between chemical components and digestible-energy concentration of cereals, and how these could be used for screening of NIRS outliers, and discusses future opportunities for application of nutritional-quality analysis using NIRS calibrations, including feed intake and portable solutions. Using advanced NIRS calibrations for digestible energy in cereals and reactive lysine in oilseed meals, pork producers will ensure that they make best use of limited resources and, as a consequence, pork will remain a nutritionally accretive food source for increasingly discerning consumers worldwide.

Use of in vitro dry matter digestibility and gas production to predict apparent total tract digestibility of total dietary fiber for growing pigs

In vitro DM disappearance (IVDMD) and gas production methods have been developed and used to measure in vivo nutrient digestibility of feed ingredients, but further validation is needed for ingredients containing high concentrations of insoluble fiber such as corn distiller's dried grains with solubles (DDGS). A 3-step in vitro procedure and resulting gas production were used to predict in vivo apparent total tract digestibility (ATTD) of total dietary fiber (TDF) among 3 sources each of wheat straw (WS), soybean hulls (SBH), and DDGS. A total of 34 barrows and 2 gilts (84 ± 7 kg BW) were used in a changeover design to determine the ATTD of 9 dietary treatments. The WS, SBH, or DDGS sources were the only ingredients containing fiber in each diet, and all diets were formulated to contain the same TDF concentration (22.3%). The in vivo experiment was conducted in 2 consecutive 13-d periods, each including a 10-d adaptation and a 3-d collection period to provide 8 replications/dietary treatment, and 0.5% TiO was added to each diet as an indigestible marker. Pigs had ad libitum access to water and were fed an amount of feed equivalent to 2.5% of initial BW in each period. The in vitro experiment was used to determine IVDMD and gas production of the 9 ingredients (5 to 8 replicates/ingredient) fed during the in vivo experiment. Gas production kinetics were fitted using a nonlinear model and analyzed using a mixed model, and predictions were evaluated using correlations and regression models. There were differences ( < 0.01) in ATTD of TDF among WS (26.7%), SBH (78.9%), and DDGS (43.0%) and among sources of DDGS (36.0 to 49.8%). Differences ( < 0.05) in IVDMD from simulated gastric and small intestinal hydrolysis were observed among WS (13.3%), SBH (18.9%), and DDGS (53.7%) and among sources of WS (12.8 to 13.8%), SBH (17.0 to 20.5%), and DDGS (52.0 to 56.9%). Differences ( < 0.05) in IVDMD from simulated large intestine fermentation (IVDMDf) were also observed among WS (23.3%), SBH (84.6%), and DDGS (69.6%) and among sources of WS (18.7 vs. 26.8%). In vitro DM disappearance from simulated total tract digestion of SBH (88.9%) and DDGS (86.1%) were greater ( < 0.01) than that of WS (33.5%). Differences ( < 0.01) in asymptotic gas production (A; mL/g DM substrate) were observed among WS (121), SBH (412), and DDGS (317), and ATTD of TDF was highly correlated with IVDMDf and A. In conclusion, low variability in ATTD of TDF and IVDMD among sources of WS and SBH evaluated in the current study may not justify the use of in vitro measurements, but in vitro fermentation accurately predicts ATTD of TDF among sources of corn DDGS.

Effect of dietary net energy concentrations on growth performance and net energy intake of growing gilts

Objective

This experiment investigated the effect of dietary net energy (NE) concentrations on growth performance and NE intake of growing gilts.

Methods

Five diets were formulated to contain 9.6, 10.1, 10.6, 11.1, and 11.6 MJ NE/kg, respectively. A metabolism trial with 10 growing pigs (average body weight [BW] = 15.9±0.24 kg) was conducted to determine NE concentrations of 5 diets based on French and Dutch NE systems in a 5×5 replicated Latin square design. A growth trial also was performed with five dietary treatments and 12 replicates per treatment using 60 growing gilts (average BW = 15.9±0.55 kg) for 28 days. A regression analysis was performed to predict daily NE intake from the BW of growing gilts.

Results

Increasing NE concentrations of diets did not influence average daily gain and average daily feed intake of growing gilts. There was a quadratic relationship (p = 0.01) between dietary NE concentrations and feed efficiency (G:F), although the difference in G:F among treatment means was relatively small. Regression analysis revealed that daily NE intake was linearly associated with the BW of growing gilts. The prediction equations for NE intake with the BW of growing gilts were: NE intake (MJ/d) = 1.442+(0.562×BW, kg), R² = 0.796 when French NE system was used, whereas NE intake (MJ/d) = 1.533+(0.614×BW, kg), R² = 0.810 when Dutch NE system was used.

Conclusion

Increasing NE concentrations of diets from 9.6 to 11.6 MJ NE/kg have little impacts on growth performance of growing gilts. Daily NE intake can be predicted from the BW between 15 and 40 kg in growing gilts.

Techniques for evaluating digestibility of energy, amino acids, phosphorus, and calcium in feed ingredients for pigs

Sound feed formulation is dependent upon precise evaluation of energy and nutrients values in feed ingredients. Hence the methodology to determine the digestibility of energy and nutrients in feedstuffs should be chosen carefully before conducting experiments. The direct and difference procedures are widely used to determine the digestibility of energy and nutrients in feedstuffs. The direct procedure is normally considered when the test feedstuff can be formulated as the sole source of the component of interest in the test diet. However, in some cases where test ingredients can only be formulated to replace a portion of the basal diet to provide the component of interest, the difference procedure can be applied to get equally robust values. Based on components of interest, ileal digesta or feces can be collected, and different sample collection processes can be used. For example, for amino acids (AA), to avoid the interference of fermentation in the hind gut, ileal digesta samples are collected to determine the ileal digestibility and simple T-cannula and index method are commonly used techniques for AA digestibility analysis. For energy, phosphorus, and calcium, normally fecal samples will be collected to determine the total tract digestibility, and therefore the total collection method is recommended to obtain more accurate estimates. Concerns with the use of apparent digestibility values include different estimated values from different inclusion level and non-additivity in mixtures of feed ingredients. These concerns can be overcome by using standardized digestibility, or true digestibility, by correcting endogenous losses of components from apparent digestibility values. In this review, methodologies used to determine energy and nutrients digestibility in pigs are discussed. It is suggested that the methodology should be carefully selected based on the component of interest, feed ingredients, and available experimental facilities.

Effects of inclusion level and adaptation period on nutrient digestibility and digestible energy of wheat bran in growing-finishing pigs

Objective

This experiment was to evaluate the effect of different inclusion levels and adaptation periods on digestible energy (DE) and the apparent total tract digestibility (ATTD) of chemical constituents in diets supplemented with wheat bran.

Methods

Thirty-six crossbred barrows with an initial body weight of 85.0±2.1 kg were allotted to 6 diets in a completely randomized block design with 6 pigs per diet. Diets included a corn-soybean basal diet and 5 additional diets which were formulated by replacing corn and soybean meal in control diet with 15%, 25%, 35%, 45%, or 55% wheat bran. The experiment lasted for 34 d, and feces were collected from d 8 to 13, 15 to 20, 22 to 27, and 29 to 34 respectively.

Results

The results showed no interaction effects between inclusion level and adaptation period on the concentration of DE and the ATTD of gross energy (GE) and crude protein (CP) in wheat bran. The DE value and ATTD of GE in wheat bran decreased (p<0.05) significantly as the inclusion level of wheat bran increased, but no difference in the ATTD of CP was observed. The ATTD of CP in wheat bran increased (p<0.10) significantly as the adaptation period for pigs was prolonged. In addition, the concentration of DE and the ATTD of GE in wheat bran decreased linearly (p<0.05) when pigs were fed either an increased level of wheat bran or given an increased adaptation period to the diets.

Conclusion

Wheat bran showed a negative effect on the concentration of DE and ATTD of GE and CP as the inclusion level increased. A longer adaptation period can gradually increase the DE value and ATTD of GE and CP in wheat bran, and at least 14 to 21 d of adaptation might be recommended for growing-finishing pigs fed the high-fiber diets with wheat bran.

Net energy of hemp hulls and processed hemp hull products fed to growing pigs and the comparison of net energy determined via indirect calorimetry and calculated from prediction equations

An experiment was conducted to determine the NE of hemp hulls (HH), extruded HH (EHH), and a blended product of HH with pea (HHP) fed to growing pigs using indirect calorimetry (IC) and to determine effects of dietary fiber on heat production (HP) and fasting HP (FHP). Twenty-four growing barrows with an average initial BW of 22.9 ± 1.75 kg were individually housed in adjustable metabolism crates. Pigs were randomly allotted to 1 of 4 dietary treatments with 6 replicates per treatment. A corn-soybean meal basal diet was prepared. Three additional diets were formulated to contain a constant ratio of corn and soybean meal and each of the test ingredients. Pigs were fed experimental diets for 16 d including 10 d for adaptation and 6 d for total collection of feces and urine to determine DE and ME of experimental diets. Pigs were then moved into IC chambers to determine HP and FHP. The apparent total tract digestibility (ATTD) of DM was greater ( < 0.01) in the HHP diet than in the HH and EHH diets but less ( < 0.01) than in the basal diet. Similarly, the ATTD of GE in the basal diet was greater ( < 0.01) compared with the HH, EHH, and HHP diets. The DE, ME, and NE of the basal diet were greater ( < 0.01) than those of the HH, EHH, and HHP diets. No significant differences were observed for the HP (on average, 1,904 kcal/kg DM) and FHP (on average, 1,320 kcal/kg DM) among treatments. However, the retained energy of pigs fed the basal diet (1,763 kcal/kg DM) was greater ( < 0.05) than for those fed the HH (1,501 kcal/kg DM) and HHP (1,482 kcal/kg DM) diets. The NE:ME ratio tended to be greater ( ≤ 0.10) for the basal diet (0.85) than for the HH (0.82), EHH (0.82), and HHP (0.83) diets. The NE of HH, EHH, and HHP determined by the IC method were 2,375, 2,320, and 2,399 kcal/kg DM, respectively, whereas values calculated using published prediction equations were 2,308, 2,161, and 2,278 kcal/kg DM, respectively. However there was no difference between determined and predicted values. In conclusion, the NE of HH, EHH, and HHP determined using the IC method were 2,375, 2,320, and 2,399 kcal/kg DM, respectively, and these values were 2.9, 7.1, and 5.2% greater, respectively, than the predicted values, although no difference was observed between determined and predicted values. However, the HP values observed for the basal diet and the diets containing high dietary fiber in the form of HH, EHH, or HHP were similar.

New feed ingredients: the insect opportunity

In the framework of sustainability and a circular economy, new ingredients for feed are desired and, to this end, initiatives for implementing such novel ingredients have been started. The initiatives include a range of different sources, of which insects are of particular interest. Within the European Union, generally, a new feed ingredient should comply with legal constraints in terms of 'yes, provided that' its safety commits to a range of legal limits for heavy metals, mycotoxins, pesticides, contaminants, pathogens etc. In the case of animal proteins, however, a second legal framework applies which is based on the principle 'no, unless'. This legislation for eradicating transmissible spongiform encephalopathy consists of prohibitions with a set of derogations applying to specific situations. Insects are currently considered animal proteins. The use of insect proteins is a good case to illustrate this difference between a positive, although restricted, modus and a negative modus for allowing animal proteins. This overview presents aspects in the areas of legislation, feed safety, environmental issues, efficiency and detection of the identity of insects. Use of insects as an extra step in the feed production chain costs extra energy and this results in a higher footprint. A measure for energy conversion should be used to facilitate the comparison between production systems based on cold- versus warm-blooded animals. Added value can be found by applying new commodities for rearing, including but not limited to category 2 animal by-products, catering and household waste including meat, and manure. Furthermore, monitoring of a correct use of insects is one possible approach for label control, traceability and prevention of fraud. The link between legislation and enforcement is strong. A principle called WISE (Witful, Indicative, Societal demands, Enforceable) is launched for governing the relationship between the above-mentioned aspects.

Procedures for determining digestibility of amino acids, lipids, starch, fibre, phosphorus, and calcium in feed ingredients fed to pigs

The proportion of nutrients that is absorbed from the intestinal tract of the pig differs among dietary ingredients; therefore, it would be desirable to determine the proportion of nutrients that is absorbed for each ingredient, but, for practical reasons, values for the digestibility of nutrients in each ingredient are used as predictors of absorption. For amino acids, starch and lipids, ileal digestibility must be determined because nutrients not absorbed in the small intestine will be fermented or changed in the large intestine, which invalidates data for total tract digestibility of these nutrients. For starch, apparent ileal digestibility is a reasonable predictor of its disappearance from the small intestine, but because of endogenous secretions of amino acids and lipids into the small intestine, standardised ileal digestibility of amino acids and true ileal digestibility of fat must be determined. For fibre, total tract digestibility is used to estimate fermentation and subsequent absorption of short-chain fatty acids, but it must be corrected for endogenous secretions. Likewise, for phosphorus and calcium, values for apparent total tract digestibility must be corrected for basal endogenous losses; consequently, standardised total tract digestibility of phosphorus and calcium is calculated and used in diet formulation. These procedures for determining the digestibility of nutrients in feed ingredients make it possible to formulate diets in which concentrations of digestible nutrients can be predicted from values for individual feed ingredients.

Different Coefficients and Exponents for Metabolic Body Weight in a Model to Estimate Individual Feed Intake for Growing-finishing Pigs

Estimation of feed intake (FI) for individual animals within a pen is needed in situations where more than one animal share a feeder during feeding trials. A partitioning method (PM) was previously published as a model to estimate the individual FI (IFI). Briefly, the IFI of a pig within the pen was calculated by partitioning IFI into IFI for maintenance (IFI_m) and IFI for growth. In the PM, IFI_m is determined based on the metabolic body weight (BW), which is calculated using the coefficient of 106 and exponent of 0.75. Two simulation studies were conducted to test the hypothesis that the use of different coefficients and exponents for metabolic BW to calculate IFI_m improves the accuracy of the estimates of IFI for pigs, and that PM is applied to pigs fed in group-housing systems. The accuracy of prediction represented by difference between actual and estimated IFI was compared using PM, ratio (RM), or averaging method (AM). In simulation studies 1 and 2, the PM estimated IFI better than the AM and RM during most of the periods (p<0.05). The use of 0.60 as the exponent and the coefficient of 197 to calculate metabolic BW did not improve the accuracy of the IFI estimates in both simulation studies 1 and 2. The results imply that the use of 197 kcal×kg BW^0.60 as metabolizable energy for maintenance in PM does not improve the accuracy of IFI estimations compared with the use of 106 kcal×kg BW^0.75 and that the PM estimates the IFI of pigs with greater accuracy compared with the averaging or ratio methods in group-housing systems.

Pigs that are divergent in feed efficiency, differ in intestinal enzyme and nutrient transporter gene expression, nutrient digestibility and microbial activity

Feed efficiency is an important trait in the future sustainability of pig production, however, the mechanisms involved are not fully elucidated. The objective of this study was to examine nutrient digestibility, organ weights, select bacterial populations, volatile fatty acids (VFA's), enzyme and intestinal nutrient transporter gene expression in a pig population divergent in feed efficiency. Male pigs (n=75; initial BW 22.4 kg SEM 2.03 kg) were fed a standard finishing diet for 43 days before slaughter to evaluate feed intake and growth for the purpose of calculating residual feed intake (RFI). Phenotypic RFI was calculated as the residuals from a regression model regressing average daily feed intake (ADFI) on average daily gain (ADG) and midtest BW0.60 (MBW). On day 115, 16 pigs (85 kg SEM 2.8 kg), designated as high RFI (HRFI) and low RFI (LRFI) were slaughtered and digesta was collected to calculate the coefficient of apparent ileal digestibility (CAID), total tract nutrient digestibility (CATTD), microbial populations and VFA's. Intestinal tissue was collected to examine intestinal nutrient transporter and enzyme gene expression. The LRFI pigs had lower ADFI (P<0.001), improved feed conversion ratio (P<0.001) and an improved RFI value relative to HRFI pigs (0.19 v. -0.14 SEM 0.08; P<0.001). The LRFI pigs had an increased CAID of gross energy (GE), and an improved CATTD of GE, nitrogen and dry matter compared to HRFI pigs (P<0.05). The LRFI pigs had higher relative gene expression levels of fatty acid binding transporter 2 (FABP2) (P<0.01), the sodium/glucose co-transporter 1 (SGLT1) (P<0.05), the glucose transporter GLUT2 (P<0.10), and the enzyme sucrase-isomaltase (SI) (P<0.05) in the jejunum. The LRFI pigs had increased populations of lactobacillus spp. in the caecum compared with HRFI pigs. In colonic digesta HRFI pigs had increased acetic acid concentrations (P<0.05). Differences in nutrient digestibility, intestinal microbial populations and gene expression levels of intestinal nutrient transporters could contribute to the biological processes responsible for feed efficiency in pigs.