Prediction of net energy value of feeds for growing pigs

Intestinal Microbiota and Microbial Metabolites Are Changed in a Pig Model Fed a High-Fat/Low-Fiber or a Low-Fat/High-Fiber Diet

The intestinal microbiota and its metabolites appear to be an important factor for gastrointestinal function and health. However, research is still needed to further elaborate potential relationships between nutrition, gut microbiota and host’s health by means of a suitable animal model. The present study examined the effect of two different diets on microbial composition and activity by using the pig as a model for humans. Eight pigs were equally allotted to two treatments, either fed a low-fat/high-fiber (LF), or a high-fat/low-fiber (HF) diet for 7 weeks. Feces were sampled at day 7 of every experimental week. Diet effects on fecal microbiota were assessed using quantitative real-time PCR, DNA fingerprinting and metaproteomics. Furthermore, fecal short-chain fatty acid (SCFA) profiles and ammonia concentrations were determined. Gene copy numbers of lactobacilli, bifidobacteria (P<0.001) and Faecalibacterium prausnitzii (P<0.05) were higher in the LF pigs, while Enterobacteriaceae were more abundant in the HF pigs (P<0.001). Higher numbers of proteins affiliated to Enterobacteriaceae were also present in the HF samples. Proteins for polysaccharide breakdown did almost exclusively originate from Prevotellaceae. Total and individual fecal SCFA concentrations were higher for pigs of the LF treatment (P<0.05), whereas fecal ammonia concentrations did not differ between treatments (P>0.05). Results provide evidence that beginning from the start of the experiment, the LF diet stimulated beneficial bacteria and SCFA production, especially butyrate (P<0.05), while the HF diet fostered those bacterial groups which have been associated with a negative impact on health conditions. These findings correspond to results in humans and might strengthen the hypothesis that the response of the porcine gut microbiota to a specific dietary modulation is in support of using the pig as suitable animal model for humans to assess diet-gut-microbiota interactions.

Data are available via ProteomeXchange with identifier PXD003447.

Comparison of growth and efficiency of dietary energy utilization by growing pigs offered feeding programs based on the metabolizable energy or the net energy system

The NE system describes the useful energy available for growth better than the ME system. The use of NE in diet formulation should maintain growth performance and carcass parameters when diets contain a diversity of ingredients. This study compared the growth performance of pigs on diets formulated using either the ME or the NE system. A total of 944 gilts and 1,110 castrates (40.8 ± 2.0 kg initial BW) were allotted to group pens and assigned to 1 of 5 different feeding programs according to a randomized complete block design. The 5 treatments included: a corn-soybean meal control diet (CTL), a corn-soybean meal diet plus corn distiller's dried grains with solubles (DDGS), formulated to be equal in ME to the CTL diet (ME-D), a corn-soybean meal diet plus corn DDGS, formulated to be equal in NE to the CTL diet (NE-D), a corn-soybean meal diet plus corn DDGS and corn germ meal, to be equal in ME to the CTL diet (ME-DC) and a corn-soybean meal diet plus corn DDGS and corn germ meal, formulated to be equal in NE to the CTL diet (NE-DC). When required, fat was added as an energy source. Pigs were harvested at an average BW of 130.3 ± 4.0 kg. Growth performance was not affected by treatment ( = 0.581, = 0. 177, and = 0.187 for ADG, ADFI, and G:F, respectively). However, carcass growth decreased with the addition of coproducts except for the NE-D treatment ( = 0.016, = 0.001, = 0.018, = 0.010, and = 0.010 for dressing percentage, HCW, carcass ADG, back fat, and loin depth, respectively). Carcass G:F and lean percentage did not differ among treatments ( = 0.109 and = 0.433, respectively). On the other hand, NE intake decreased ( = 0.035) similarly to that of carcass gain, suggesting a relationship between NE intake and energy retention. Calculations of NE per kilogram of BW gain differed among treatments ( = 0.010), but NE per kilogram of carcass was similar among treatments ( = 0.640). This suggests that NE may be better than ME at explaining the carcass results. Finally, ME intake and ME per kilogram of BW gain were not different among treatments ( = 0.112), but ME per kilogram of carcass gain was different among treatments ( = 0.048). In conclusion, the sequential addition of coproducts in diets formulated on an NE or ME basis can result in similar growth performance, but carcass parameters may be affected independently of the energy system used. However, formulating diets based on NE tended to improve predictability of growth, especially carcass parameters.

Effects of exogenous phytase and xylanase, individually or in combination, and pelleting on nutrient digestibility, available energy content of wheat and performance of growing pigs fed wheat-based diets

OBJECTIVE

Two experiments were conducted to determine the effects of adding exogenous phytase and xylanase, individually or in combination, as well as pelleting on nutrient digestibility, available energy content of wheat and the performance of growing pigs fed wheat-based diets.

METHODS

In Experiment 1, forty-eight barrows with an initial body weight of 35.9±0.6 kg were randomly assigned to a 2×4 factorial experiment with the main effects being feed form (pellet vs meal) and enzyme supplementation (none, 10,000 U/kg phytase, 4,000 U/kg xylanase or 10,000 U/kg phytase plus 4,000 U/kg xylanase). The basal diet contained 97.8% wheat. Pigs were placed in metabolic cages for a 7-d adaptation period followed by a 5-d total collection of feces and urine. Nutrient digestibility and available energy content were determined. Experiment 2 was conducted to evaluate the effects of pelleting and enzymes on performance of wheat for growing pigs. In this experiment, 180 growing pigs (35.2±9.0 kg BW) were allocated to 1 of 6 treatments according to a 2×3 factorial treatment arrangement with the main effects being feed form (meal vs pellet) and enzyme supplementation (0, 2,500 or 5,000 U/kg xylanase).

RESULTS

In Experiment 1, there were no interactions between feed form and enzyme supplementation. Pelleting reduced the digestibility of acid detergent fiber (ADF) by 6.4 percentage units (p<0.01), increased the digestibility of energy by 0.6 percentage units (p<0.05), and tended to improve the digestibility of crude protein by 0.5 percentage units (p = 0.07) compared with diets in mash form. The addition of phytase improved the digestibility of phosphorus (p<0.01) and calcium (p<0.01) by 6.9 and 7.6 percentage units respectively compared with control group. Adding xylanase tended to increase the digestibility of crude protein by 1.0 percentage units (p = 0.09) and increased the digestibility of neutral detergent fiber (NDF) (p<0.01) compared with control group. Supplementation of the xylanase-phytase combination improved the digestibility of phosphorus (p<0.01) but impaired NDF digestibility (p<0.05) compared with adding xylanase alone. In Experiment 2, adding xylanase increased average daily gain (p<0.01) and linearly improved the feed:gain ratio (p<0.01) compared with control group.

CONCLUSION

Pelleting improved energy digestibility but decreased ADF digestibility. Adding xylanase increased crude protein digestibility and pig performance. Phytase increased the apparent total tract digestibility of phosphorus and calcium. The combination of phytase-xylanase supplementation impaired the effects of xylanase on NDF digestibility.

The effects of feeding sorghum dried distillers grains with solubles on finishing pig growth performance, carcass characteristics, and fat quality

The objective of this study was to determine the effects of feeding sorghum dried distillers grains with solubles (DDGS) in grain sorghum– or corn-based diets on pig growth performance, carcass characteristics, and carcass fat quality. A total of 288 finishing pigs (BW 58.8 ± 4.43 kg; Line TR 4 × 1050, PIC, Hendersonville, TN) were used in a 73-d study. Pigs were allotted to 1 of 6 dietary treatments with 6 pens of 8 pigs per treatment. Treatments included grain sorghum–based diets with 0%, 15%, 30%, or 45% sorghum DDGS (29.0% CP, 7.2% ether extract); a grain sorghum–based diet with 30% corn DDGS (25.7% CP, 8.7% ether extract); and a corn-based diet with 30% corn DDGS. The diets were formulated to 0.95%, 0.83%, and 0.71% standardized ileal digestible Lys in phases 1, 2, and 3, respectively, and were not balanced for energy. On d 73, a subsample of 72 pigs (1 barrow and 1 gilt/pen) was harvested at Kansas State University’s Meats Laboratory. Carcass traits were calculated, as well as 10th-rib LM color, marbling and firmness, and fat color score. Fat samples from the 10th rib were collected and analyzed for fatty acid profile, which was used to calculate iodine value (IV). The remaining pigs were transported to a commercial packing plant (Triumph Foods, St. Joseph, MO) for carcass measurement and jowl IV determinations. Overall, increasing the dietary sorghum DDGS reduced (linear, P < 0.01) ADG and increased (linear, P < 0.01) back fat IV. Pigs fed increasing sorghum DDGS had decreased 10th-rib fat a* (less red) and b* (less yellow; P < 0.01 and 0.06, respectively). No differences were observed in growth performance or back fat IV among pigs fed corn- or grain sorghum–based diets with 30% corn DDGS. Pigs fed the grain sorghum–based diet with 30% corn DDGS had fat color that was more yellow (b*; P < 0.03) than that of pigs fed the grain sorghum–based diet with 30% sorghum DDGS. Pigs fed the grain sorghum–based diet with 30% sorghum DDGS also had decreased back fat IV (P < 0.01) and fat that was whiter (L*; P < 0.02) than that of those fed the grain sorghum–based diet with corn DDGS. Pigs fed grain sorghum with 30% sorghum DDGS had lower (P < 0.01) back fat IV than pigs fed corn with 30% corn DDGS. Feeding a grain sorghum–based diet with increasing sorghum DDGS reduces ADG when diets are not balanced for energy but, when fed at 30% of the diet, produces firmer pork fat than feeding a corn-based diet with 30% corn DDGS, which may be preferred for pork export markets.

Body fat mobilization during lactation in high-producing sows fed varied omega-6 to omega-3 fatty acid ratios

The effects of reducing dietary omega (n)-6 to n-3 fatty acid (FA) ratios on body fat mobilization in lactating sows (n = 100) were investigated. Treatments consisted of a control (tallow, low polyunsaturated FA, 8:1 n-6:n-3 ratio), 3 diets with plant oil based ratios (9:1P, 5:1P, and 1:1P), and a 5:1 fish oil diet (5:1F). An epinephrine [1.6 μg kg−1 body weight (BW)] challenge was used to measure adipose tissue lipolytic activity (glycerol, NEFA, and leptin) on d 5 of lactation from a subset of sows (9:1P and 1:1P groups) fitted with jugular catheters. Lactation feed intake was greatest for control and 5:1P-fed sows (8.3 kg d−1), lowest for 1:1P-fed sows (7.4 kg d−1), and intermediate for 9:1P- and 5:1F-fed sows (7.7 kg d−1; P = 0.047). Piglet average daily gain (ADG) and estimated milk output were unaffected by diet (P > 0.10). The 1:1P-fed sows had (P < 0.10) greater backfat thickness, increased circulating leptin, and reduced feed intake, which are correlated (P < 0.10) with increased circulating glycerol and NEFA. Sows fed a plant oil based 1:1 n-6:n-3 FA ratio appeared to be in a state of negative energy balance; however, as no effects were observed on piglet ADG, these sows were able to provide the same level of nutrients to their offspring as the 9:1P fed sows.

Nutrient digestibility of solvent-extracted Brassica napus and Brassica juncea canola meals and their air-classified fractions fed to ileal-cannulated grower pigs

Energy and nutrient digestibility of solvent-extracted canola meal (CM) is limited in pigs by its relatively high fiber content. The seed hull, which greatly contributes to the fiber content of CM, is denser than the oil-free cotyledon. By utilizing streams of air, air classification partially separates these seed components on the basis of their different sizes and densities to produce a low-fiber, light-particle fraction and a high-fiber, heavy-particle fraction. Compared with parent CM, ADF and NDF were reduced by 31.9% and 29.5% in the light-particle fraction and were enriched by 16.5% and 9.0% in the heavy-particle fraction (DM basis), respectively. Particle size was 638, 18.9, and 76.1 µm for the parent CM and light- and heavy-particle fractions, respectively. To determine the nutrient digestibility of CM and their air-classified fractions, Brassica napus and B. juncea CM and their 2 air-classified fractions were evaluated in a 2 × 3 factorial arrangement together with a basal diet and an N-free diet. The experiment was conducted as an 8 × 8 Latin square in which diets contained 40% B. napus or B. juncea CM or their air-classified fractions and 60% basal diet. Digesta data from pigs fed the N-free diet served to subtract basal endogenous AA losses. Eight ileal-cannulated barrows (32 kg initial BW) were fed the 8 diets at 2.7 times maintenance DE for eight 11-d periods. At the end of each period, feces were collected for 48 h, and ileal digesta were collected for two 12-h periods. The DE and calculated NE values and the apparent total tract digestibility (ATTD) of GE were 6.3%, 10.0%, and 7.8% greater (P < 0.001) for B. juncea CM than for B. napus CM; 6.1%, 10.8%, and 5.3% greater (P < 0.001) for the light-particle fraction than for parent CM; and 5.4%, 7.2%, and 3.8% lower (P < 0.001) for the heavy-particle fraction than for parent CM, respectively. The standardized ileal digestibilities (SID) of His, Ile, Val, Asp, and Tyr were greater (P < 0.05) for B. juncea CM than for B. napus CM. The SID of CP and AA were greater (P < 0.01) in the light-particle fraction than in the heavy-particle fraction. The SID of Trp, Glu, Pro, and Tyr were greater (P < 0.05) in the light-particle fraction than in parent CM. In conclusion, B. juncea CM had greater energy and AA digestibility than B. napus CM because of reduced fiber content. Air classification of CM increased its energy and AA digestibility in the light-particle fraction for pigs because of the reduced dietary fiber content and decreased particle size.

Effect of the inclusion of dry pasta by-products at different levels in the diet of typical Italian finishing heavy pigs: Performance, carcass characteristics, and ham quality

The effect of pasta inclusion in finishing pig diets was evaluated on growth performance, carcass characteristics, and ham quality. Pigs (144) were assigned to 4 diets with different pasta levels: 0 (control, corn-based diet), 30, 60, or 80%. Pigs fed pasta had greater (linear, P<0.01) feed intakes than controls. Pasta increased (quadratic, P<0.01) carcass weight and dressing percentage reaching the highest values at 30% inclusion level, and reduced (linear, P<0.01) the Longissimus thoracis et lumborum thickness. Pasta decreased (linear, P<0.01) linoleic acid and polyunsaturated fatty acid levels in subcutaneous (fresh and seasoned hams) and intramuscular (seasoned hams) fat, and enhanced saturated fatty acid content in subcutaneous fat (fresh hams: quadratic, P<0.01; seasoned hams: linear, P=0.03). Proteolysis index, colour, weight losses, and sensory properties (excepted extraneous taste) of the hams were unaffected by the pasta. Pasta could be considered as an ingredient in the diet for typical Italian finishing heavy pigs.

Growth Performance of Early Finishing Gilts as Affected by Different Net Energy Concentrations in Diets

The objectives of the current experiment were to study the response of the growth performance of early finishing gilts to different net energy (NE) concentrations in diets, and to compare the NE values of diets between calculated NE values and measured NE values using French and Dutch CVB (Centraal Veevoederbureau; Central Bureau for Livestock Feeding) NE systems. In a metabolism trail, the NE concentrations in five diets used for the growth trial were determined based on digestible nutrient concentrations, digestible energy, and metabolizable energy using a replicated 5×5 Latin square design with 10 barrows (initial body weight [BW], 39.2±2.2 kg). In a growth trial, a total of 60 early finishing gilts (Landrace×Yorkshire; initial BW, 47.7±3.5 kg) were allotted to five dietary treatments of 8.0, 9.0, 10.0, 11.0, and 12.0 MJ NE/kg (calculated, as-is basis) with 12 replicate pens and one pig per pen in a 42-d feeding experiment. The NE and amino acid (AA) concentrations in all diets were calculated based on the values from NRC (2012). Ratios between standardized ileal digestible AA and NE concentrations in all diets were closely maintained. Pigs were allowed ad libitum access to feed and water. Results indicated that calculated NE concentrations in diets (i.e., five dietary treatments) were close to measured NE concentrations using French NE system in diets. The final BW was increased (linear and quadratic, p<0.05) with increasing NE concentrations in diets. Furthermore, average daily gain (ADG) was increased (linear and quadratic, p<0.01) with increasing NE concentrations in diets. There was a quadratic relationship (p<0.01) between average daily feed intake and NE concentrations in diets. Feed efficiency (G:F) was also increased (linear, p<0.01) as NE concentrations in diets were increased. The NE intake per BW gain (kcal NE/kg of BWG) was increased (linear, p<0.01) with increasing NE concentrations in diets that were predicted from both French and Dutch CVB NE systems. Linear regression indicated that predictability of daily NE intake from the BW of pigs was very low for both French (R², 0.366) and Dutch CVB (R², 0.374) NE systems. In conclusion, increasing NE concentrations in diets increase BW, ADG, G:F, and NE intake per BW gain of early finishing gilts. The BW of early finishing gilts is not a good sole variable for the prediction of daily NE intake.

Characteristics of lipids and their feeding value in swine diets

In livestock diets, energy is one of the most expensive nutritional components of feed formulation. Because lipids are a concentrated energy source, inclusion of lipids are known to affect growth rate and feed efficiency, but are also known to affect diet palatability, feed dustiness, and pellet quality. In reviewing the literature, the majority of research studies conducted on the subject of lipids have focused mainly on the effects of feeding presumably high quality lipids on growth performance, digestion, and metabolism in young animals. There is, however, the wide array of composition and quality differences among lipid sources available to the animal industry making it essential to understand differences in lipid composition and quality factors affecting their digestion and metabolism more fully. In addition there is often confusion in lipid nomenclature, measuring lipid content and composition, and evaluating quality factors necessary to understand the true feeding value to animals. Lastly, advances in understanding lipid digestion, post-absorption metabolism, and physiological processes (e.g., cell division and differentiation, immune function and inflammation); and in metabolic oxidative stress in the animal and lipid peroxidation, necessitates a more compressive assessment of factors affecting the value of lipid supplementation to livestock diets. The following review provides insight into lipid classification, digestion and absorption, lipid peroxidation indices, lipid quality and nutritional value, and antioxidants in growing pigs.

Net energy content of dry extruded-expelled soybean meal fed with or without enzyme supplementation to growing pigs as determined by indirect calorimetry

Two experiments were conducted to determine the NE content of dry extruded-expelled soybean (DESBM) and the effect of a multienzyme carbohydrase (MC) mixture on the NE content of DESBM and to determine the effect of diet design on NE values in growing pigs using indirect calorimetry (IC). In Exp. 1, 24 barrows (19.6 ± 0.51 kg BW) were allotted in a completely randomized design to 4 dietary treatments: a corn–soybean meal basal diet (Diet A), a diet containing Diet A and DESBM in an 80:20 ratio with a constant CP (Diet B), a diet with an 80:20 ratio of Diet A and DESBM with a constant corn:soybean meal ratio (Diet C), and a diet with simple substitution of Diet A with DESBM in an 80:20 ratio (Diet D). Pigs were fed in metabolism crates for a period of 16 d to determine the DE and ME and thereafter were moved into an indirect calorimeter where O2 consumption and CO2 production were measured to determine heat production and fasting heat production. The NE content of DESBM was calculated (difference method) to be 2,632, 2,548 and 2,540 kcal/kg DM in diets B, C, and D, respectively. Respective values obtained with published prediction equations were 2,624, 2,530 and 2,436 kcal/kg. In Exp. 2, 24 barrows (16.9 ± 0.76 kg BW) were randomly allotted to 1 of 4 treatments. The diets were a corn–soybean meal basal diet and a diet containing the basal diet and DESBM in an 80:20 ratio with a constant corn:soybean meal ratio with or without 2 levels (0.05% and 0.1%) of MC. The experimental procedures were similar to those described in Exp. 1. Enzyme supplementation improved (P < 0.0001) the DE, ME, and NE content of the DESBM. Multienzyme carbohydrase at 0.05% and 0.1% of the diet improved NE values of DESBM by 4.9% and 3.7%, respectively. In conclusion, the NE values of DESBM obtained with the IC method were higher than the values obtained with prediction equations; the disparity was least when diets were formulated with a constant CP level. However, as the difference method was used to determine the NE of ingredient, it is more appropriate to maintain a constant ratio between the ingredients. Also, the NE value of DESBM obtained for diets C and D were not different. Hence, the average NE value of DESBM evaluated was 2,544 kcal/kg DM. Enzyme supplementation improved the NE content of DESBM fed to growing pigs.

Empiric narrowing of the net energy value of reduced-oil corn distillers’ dried grain with solubles for growing-finishing pigs

Smit, M. N., Zamora, V., Young, M. G., Campbell, N., Uttaro, B. and Beltranena, E. 2015. Empiric narrowing of the net energy value of reduced-oil corn distillers’ dried grain with solubles for growing-finishing pigs. Can. J. Anim. Sci. 95: 225–241. This study attempted to empirically narrow down the net energy (NE) value of reduced-oil corn distillers’ dried grains and solubles (RO-cDDGS) by evaluating the response in pig growth performance, live backfat and loin depth, carcass traits, and primal pork cuts tissue composition to feeding diets formulated increasing the assumed NE value of RO-cDDGS, expecting a brisk change in slope of the response at the point at which the NE value of RO-cDDGS would be identified. In total, 1056 cross-bred pigs (31.7 kg) housed in 48 pens by gender were fed dietary regimens including 30% RO-cDDGS (6.7% ether extract) with assumed NE values of 1.7, 1.85, 2.0, 2.15, 2.3, or 2.45 Mcal kg−1over five growth periods (Grower 1: days 0–21, Grower 2: days 22–42, Grower 3: days 43–63, Finisher 1: days 64–76, Finisher 2: day 77 to market weight). Pig body weights were measured and feed disappearance (ADFI) was calculated by pen on days 0, 21, 42, 63, 76 and weekly thereafter until target slaughter weight (120 kg). For the entire trial (days 0–76), increasing the assumed NE value of RO-cDDGS linearly increased (P<0.01) ADFI and total lysine intake, did not affect NE intake and daily weight gain (ADG), quadratically decreased (P<0.05) feed efficiency, linearly decreased (P<0.05) live backfat depth and backfat:loin depth ratio, and did not affect carcass characteristics or pork primal cut tissue composition. Segmented regression only identified a change in slope for carcass ADG and lean ADG at 1.85 Mcal kg−1. These results indicate that the experimental approach taken was not reliable in narrowing down the NE value of RO-cDDGS because the decrease in dietary NE was too small (0.03 Mcal kg−1d), which limited the change in dietary Lys:NE ratio with increasing assumed NE value of RO-cDDGS. The approach resulted in progressive, but small changes in slope rather than a clearly identifiable point where one could conclude that the incremental dietary energy contribution from RO-cDDGS changed the response in a given variable.

Prediction of the net energy value of broiler diets

Thirty pelleted diets were given to broiler chickens (eight birds per diet; 21 to 35 days of age) for individual in vivo measurements of dietary net energy (NE) value, using three trials with 10 diets/trial. Amino acid formulation of diets was done on the basis of ratios to CP. NE was measured according to the body analysis method. The basal metabolism component of NE values was calculated on the basis of mean metabolic weight using a coefficient obtained in a previous experiment. Information about apparent metabolisable energy (AME) value of diets, AME corrected to zero nitrogen retention (AMEn) and digestibilities of proteins, lipids, starch and sugars was available from a previous publication. In each trial, mean NE/AME ratios of diets varied by about 6%. From the multiple regressions (n=30) expressing NE and AMEn values as functions of digestible component contents, it was deduced that the NE/AMEn ratios assigned to dietary components were 0.760, 0.862, 0.806, 0.690 and 0.602 for CP, lipids, starch, (sucrose+glucose) and fermentable sugars (α-galacto-oligosaccharides and lactose), respectively. The NE/AME ratio of CP was 0.680. Regression calculations showed that the NE values assigned to individual birds (n=240) could also be predicted with diet AMEn values (NE=0.80 AMEn; R 2=0.770) or with an equation combining AMEn value and CP/AMEn ratio (R 2=0.773). The latter ratio was found to be the only additional parameter that was significant when added in the NE regression scheme based on AMEn.

Low-protein amino acid-supplemented diets for growing pigs: effect on expression of amino acid transporters, serum concentration, performance, and carcass composition

Pigs fed protein-bound AA appear to have a higher abundance of AA transporters for their absorption in the jejunum compared with the duodenum. However, there is limited data about the effect of dietary free AA, readily available in the duodenum, on the duodenal abundance of AA transporters and its impact on pig performance. Forty-eight pigs (24.3 kg initial BW) distributed in 4 treatments were used to evaluate the effect of the CP level and form (free vs. protein bound) in which AA are added to diets on the expression of AA transporters in the 3 small intestine segments, serum concentration of AA, and performance. Dietary treatments based on wheat and soybean meal (SBM) were 1) low-CP (14%) diet supplemented with L-Lys, L-Thr, DL-Met, L-Leu, L-Ile, L-Val, L-His, L-Trp, and L-Phe (LPAA); 2) as in the LPAA but with added L-Gly as a N source (LPAA+N); 3) intermediate CP content (16%) supplemented with L-Lys HCl, L-Thr, and DL-Met (MPAA); and 4) high-CP (22%) diet (HP) without free AA. At the end of the experiment, 8 pigs from LPAA and HP were sacrificed to collect intestinal mucosa and blood samples and to dissect the carcasses. There were no differences in ADG, ADFI, G:F, and weights of carcass components and some visceral organs between treatments. Weights of the large intestine and kidney were higher in HP pigs (P < 0.01). Expression of b(0,+) in the duodenum was higher in pigs fed the LPAA compared with the HP diet (P= 0.036) but there was no difference in the jejunum and ileum. In the ileum, y+ L expression tended to be higher in pigs fed the LPAA diet (P = 0.098). Expression of b(0,+) in LPAA pigs did not differ between the duodenum and the jejunum, but in HP pigs, the expression of all AA transporters was higher in the jejunum than in the duodenum or ileum (P < 0.05). The serum concentration of Arg, His, Ile, Leu, Phe, and Val was higher but serum Lys and Met were lower in pigs fed the HP diet (P < 0.05). These results indicate that LPAA can substitute up to 8 percentage units of protein in HP wheat-SBM diets without affecting pig performance; nonessential N does not seem to be limiting in very low-protein wheat-SBM diets for growing pigs. Also, the inclusion of free AA in the diet appears to affect their serum concentration and the expression of the AA transporter b0,+ in the duodenum of pigs.

Nutritive value of wheat concentrated distillers solubles in diets for growing pigs

Two experiments (Exp.) were conducted to determine the nutritive value of wheat-derived wet concentrated distillers solubles (CDS) for growing pigs. In Exp. 1, standardised ileal digestibility (SID) of amino acids (AA) was determined by the difference method, using six ileally cannulated barrows (initial bodyweight (BW) of 31 ± 2.9 kg). The pigs were fed a casein-corn starch-based diet supplemented with wheat CDS so that about half of the crude protein (CP) originated from either wheat CDS or from casein. In Exp. 2, 12 barrows with an initial BW of 17 ± 0.9 kg were used to determine digestible energy (DE) content, and to calculate metabolisable energy (ME) and net energy (NE) content of wheat CDS. Animals were fed either a casein-corn starch-based basal diet or a CDS diet containing 470 g/kg of the basal diet and 530 g/kg wheat CDS on a dry matter (DM) basis. Values of SID of CP and AA in Exp. 1 amounted to 85, 74, 83 and 70% for CP, lysine, methionine and threonine, respectively. The DE, ME and NE contents of wheat CDS were 16.8, 15.8 and 11.1 MJ/kg DM, respectively. It can be concluded that SID of CP and AA and also the energy content in wheat CDS are substantially higher than corresponding values reported in international tables with information on nutritional value of dried co-products of bioethanol production.

Characterization of dietary energy in Swine feed and feed ingredients: a review of recent research results

Feed is single most expensive input in commercial pork production representing more than 50% of the total cost of production. The greatest proportion of this cost is associated with the energy component, thus making energy the most important dietary in terms of cost. For efficient pork production, it is imperative that diets are formulated to accurately match dietary energy supply to requirements for maintenance and productive functions. To achieve this goal, it is critical that the energy value of feeds is precisely determined and that the energy system that best meets the energy needs of a pig is used. Therefore, the present review focuses on dietary supply and needs for pigs and the available energy systems for formulating swine diets with particular emphasis on the net energy system. In addition to providing a more accurate estimate of the energy available to the animal in an ingredient and the subsequent diet, diets formulated using the this system are typically lower in crude protein, which leads to additional benefits in terms of reduced nitrogen excretion and consequent environmental pollution. Furthermore, using the net energy system may reduce diet cost as it allows for increased use of feedstuffs containing fibre in place of feedstuffs containing starch. A brief review of the use of distiller dried grains with solubles in swine diets as an energy source is included.

Effect of feeding level on ileal and total tract digestibility of nutrients and energy from soybean meal-based diets for piglets

A total of 36 piglets with an initial body weight (BW) of 5.6 ± 0.7 kg, fitted with simple T-cannulas at the distal ileum, were used to evaluate the effect of three graded feeding levels (50, 75 or 100 g/kg BW(0.75) day) on apparent ileal digestibility (AID) and total tract digestibility (ATTD) of dry matter (DM), nitrogen (N) and energy, and on ATTD of organic matter (OM), ether extracts (EE), neutral detergent fibre (NDF), acid detergent fibre (ADF) and digestible (DE), metabolisable (ME) and net energy (NE) content in soybean meal (SBM)-casein-cornstarch-based diets. The AID of DM, N and energy and ATTD of NDF, ADF and EE in the diets were not affected (p > 0.05) by the feed intake (FI) level. There was a small decrease in ATTD of DM, N (CP), OM, ash and energy, and in DE, ME and NE content in the diets (p < 0.05) with increasing FI level. The net disappearance in the large intestine (in % of ileal recovery) decreased for DM, N and energy (p < 0.05) with increasing FI level. The design of the study allowed for estimating ileal endogenous loss of N and total tract endogenous loss of ash, N and EE, for estimating corresponding true ileal and total tract digestibility values, and for estimating urinary endogenous N loss. High variability in estimates of ileal endogenous N loss and total tract endogenous losses of N, EE and ash reflects great variation in individual endogenous losses between animals. Estimation of true total tract digestibility of N, EE and ash by regression analysis was affected by their decrease in ATTD with increasing FI level, as estimates for true digestibility were lower compared to their apparent values. The present results suggest that FI level can affect both apparent and true total tract nutrient digestibility in piglets.

Changing the omega-6 to omega-3 fatty acid ratio in sow diets alters serum, colostrum, and milk fatty acid profiles, but has minimal impact on reproductive performance

This experiment tested the hypothesis that reducing the omega-6 (n-6) to omega-3 (n-3) fatty acid (FA) ratio in sow diets will improve performance, characterized by increased litter size, decreased preweaning mortality, and improved growth performance. Second, we determined if the FA profile in sow and piglet blood, colostrum, and milk are altered when sows are fed diets with varied n-6:n-3 ratios and if the dietary FA ratio impacts circulating concentrations of IgG, IgA, eicosapentaenoic (EPA), or docosahexaenoic (DHA) acid. Sows (n=150) were assigned to 1 of 5 treatments (each divided into gestation and lactation diets) on d 80 of gestation. Period 1 (P1) is defined as d 80 of gestation to weaning and Period 2 (P2) refers to the subsequent breeding to weaning. Diets were wheat and barley based (5% crude fat) and treatments consisted of a control (tallow), 3 diets with plant oil-based n-6:n-3 ratios (9:1P, 5:1P, and 1:1P), and a 5:1 fish oil diet (5:1F). Litter size was unaffected by treatment during P1 and P2 (P>0.10). In P1, birth weight was unaffected by diet (P>0.10); however, weaning weight (P=0.019) and ADG from birth to weaning (P=0.011) were greatest for piglets born to 9:1P and 5:1P sows. During P2, 5:1F sows consumed 10% less feed during lactation (P=0.036), tended to have reduced piglet birth weights (P=0.052), and piglet weaning weight was reduced by 0.8 kg (P=0.040) relative to the other diets. Colostrum and piglet serum IgA and IgG concentrations were unaffected by diet (P>0.10). Serum n-3 FA were greatest in sows (P<0.01) consuming 1:1P and 5:1F diets and in their offspring (P=0.014). Serum α-linolenic acid (ALA) was greatest in 1:1P sows and EPA and DHA were greatest in 5:1F sows (P<0.01). In pre-suckle piglet serum, ALA did not differ among treatment groups (P>0.10). Relative to piglets of sows consuming the control diet, EPA was 2.5-fold greater in the 1:1P group and 4-fold greater in 5:1F group (P<0.01) before suckling. In post-suckle samples, ALA was greatest in piglets from the 1:1P sows (P<0.01) and EPA and DHA were greatest in piglets from the 5:1F sows (P<0.01). Feeding diets with plant-based n-6:n-3 ratios of 5:1 or 1:1 did not impact performance relative to a control group but improved the conversion of ALA into EPA and increased the transfer of n-3 to piglets through milk. When a fish-based 5:1 ratio diet was fed, pre-weaning mortality was increased, and piglet birth and weaning weights decreased.

Effects of co-products from the corn-ethanol industry on body composition, retention of protein, lipids and energy, and on the net energy of diets fed to growing or finishing pigs

BACKGROUND

Conventional distillers dried grains with solubles (DDGS-CV), uncooked distillers dried grains with solubles (DDGS-BPX) and high-protein distillers dried grains (HP-DDG) are used in diets for pigs to provide protein and energy. These ingredients may have different effects on body composition and energy retention. Therefore, an experiment was conducted to determine effects of DDGS-CV, DDGS-BPX and HP-DDG on body composition and on retention of protein, lipids, and energy when fed to growing or finishing pigs.

RESULTS

The total organ weight was greater (P < 0.05) for finishing pigs fed the HP-DDG diet than for finishing pigs fed the basal diet or the DDGS-CV diet. Finishing pigs fed the DDGS-CV diet had greater (P < 0.05) lipid gain than pigs fed the other diets, and the net energy (NE) for DDGS-CV was greater (P < 0.05) than for DDGS-BPX, but the NE value of HP-DDG was not different from that of DDGS-CV or DDGS-BPX.

CONCLUSION

Inclusion of up to 30% DDGS or HP-DDG in diets fed to growing or finishing pigs will not affect body composition or the retention of energy, protein and lipids, regardless of the stage of growth of pigs. The NE value of DDGS-BPX and HP-DDG is not affected by the stage of growth of pigs, but the NE value of DDGS-CV is greater in finishing than in growing pigs.

Effect of sorghum distillers dried grains with solubles and microbial enzymes on metabolizable and net energy values of broiler diets

There is generally no information regarding the influence of distillers dried grains with solubles (DDGS) on the net energy (NE) value of broiler diets. It was hypothesized that the ME content of DDGS may overestimate its productive energy, leading to higher heat increment when used in broiler diets. Furthermore, it was of interest to investigate the potential benefits of a mixture of carbohydrases and protease on energy partitioning in diets containing DDGS. In this study, 2 evaluations, comparative slaughter (CS) or indirect calorimetry (IC), were conducted using the same batch of birds and feed. Two levels of DDGS (0 or 30%) without or with an enzyme mixture were used in a 2 × 2 factorial arrangement of treatments. The CS evaluation used 240 male Ross 308 broiler chicks with 6 replicates (10 birds each) per treatment from d 18 to 28. Carcass energy values were examined in 2 birds per replicate on each of d 18 and 28 to determine heat production (HP), NE, and ME. The IC evaluation used 32 birds acclimatized to 16 closed-circuit calorimeters (2 birds per chamber) following energy partitioning measurement by gaseous exchange and total excreta collection from 18 to 24 d. Birds fed DDGS had increased feed efficiency during starter and grower phases (P < 0.001). The CS showed no difference in HP between birds fed diets with or without DDGS. When measured by IC, birds fed diets containing DDGS had higher HP and lower NE (P < 0.01). Enzyme supplementation had no effect on HP, ME, or NE:ME ratio measured using CS or IC but increased NE and NE intake (P < 0.01) from d 18 to 28. Carcass fat retention was decreased (P < 0.05) and there was a lower NE (P < 0.01) in birds fed the DDGS-diets. This study showed that 30% dietary DDGS affects energy partitioning in broilers with more heat produced, decreased dietary NE, and less fat retained in the carcass.

Dry fractionation creates fractions of wheat distillers dried grains and solubles with highly digestible nutrient content for grower pigs

Nutrient digestibility in distillers dried grains with solubles (DDGS) is limited by constraints such as particle size and fiber. Wheat DDGS contains more fiber than corn DDGS that may reduce its nutritional value in swine feeds. Dry fractionation may create DDGS fractions with low and high fiber content; therefore, wheat DDGS was processed sequentially using a vibratory sifter and gravity table. Sufficient material was obtained from 3 wheat DDGS fractions that differed in particle size from fine to coarse (Fraction A [FA], Fraction C [FC], and Fraction D [FD]). Five cornstarch-based diets were mixed that contained either 40% wheat DDGS, 30% FA, 30% FC plus 10% soybean meal (SBM), 30% FD plus 15% SBM, or 35% SBM. A sixth, N-free diet served to subtract basal endogenous AA losses and as control for energy digestibility calculations. Six ileal-cannulated barrows (29 kg BW) were fed 6 diets at 2.8 times maintenance for DE in six 9-d periods as a 6 × 6 Latin square. Feces and ileal digesta were collected sequentially for 2 d each. Wheat DDGS FA, FC, and FD were 258, 530, and 723 μm in mean particle size and contained 44.8, 39.3, and 33.8% CP and 29.1, 35.1, and 37.5% in NDF, respectively. The apparent total tract digestibility (ATTD) of GE was greater (P < 0.05) for SBM than wheat DDGS, was greater (P < 0.05) for FA than wheat DDGS, and did not differ between FC, FD, and wheat DDGS. The standardized ileal digestibility (SID) did not differ between SBM and wheat DDGS (P > 0.05) for most AA. The SID of Arg, Lys, Trp, and available Lys was greater (P < 0.05) for FD than wheat DDGS but was similar for FA, FC, and wheat DDGS and was greater (P < 0.05) for FD than SBM. The DE and NE value was greater (P < 0.05) for SBM, FA, and FC than wheat DDGS and did not differ between FD and wheat DDGS. The SID content of indispensable AA and available Lys was greater (P < 0.05) for SBM than wheat DDGS. The SID content of Ile, Leu, Met, Phe, and Val was greater (P < 0.05) for FA than wheat DDGS but did not differ for indispensable AA between FC and wheat DDGS. The SID content of His, Ile, Leu, Met, and Phe was lower (P < 0.05) for FD than wheat DDGS. In conclusion, dry fractionation creates DDGS fractions with a differing chemical composition. Fine particle fractions contain less fiber and more CP than coarse particle fractions, but their AA digestibility was lower, likely due to most of the solubles being fine particles that are more susceptible to AA damage than protein entrapped in particles of larger size.

Determination and prediction of digestible and metabolizable energy from the chemical composition of chinese corn gluten feed fed to finishing pigs

Two experiments were conducted to determine the digestible energy (DE) and metabolizable energy (ME) contents of corn gluten feed (CGF) for finishing pigs and to develop equations predicting the DE and ME content from the chemical composition of the CGF samples, as well as validate the accuracy of the prediction equations. In Exp. 1, ten CGF samples from seven provinces of China were collected and fed to 66 finishing barrows (Duroc×Landrace×Yorkshire) with an initial body weight (BW) of 51.9±5.5 kg. The pigs were assigned to 11 diets comprising one basal diet and 10 CGF test diets with six pigs fed each diet. The basal diet contained corn (76%), dehulled soybean meal (21%) and premix (3%). The ten test diets were formulated by substituting 25% of the corn and dehulled soybean meal with CGF and contained corn (57%), dehulled soybean meal (15.75%), CGF (24.25%) and premix (3%). In Exp. 2, two additional CGF sources were collected as validation samples to test the accuracy of the prediction equations. In this experiment, 18 barrows (Duroc×Landrace×Yorkshire) with an initial BW of 61.1±4.0 kg were randomly allotted to be fed either the basal diet or two CGF containing diets which had a similar composition as used in Exp. 1. The DE and ME of CGF ranged from 10.37 to 12.85 MJ/kg of dry matter (DM) and 9.53 to 12.49 MJ/kg of DM, respectively. Through stepwise regression analysis, several prediction equations of DE and ME were generated. The best fit equations were: DE, MJ/kg of DM = 18.30-0.13 neutral detergent fiber-0.22 ether extract, with R(2) = 0.95, residual standard deviation (RSD) = 0.21 and p<0.01; and ME, MJ/kg of DM = 12.82+0.11 Starch-0.26 acid detergent fiber, with R(2) = 0.94, RSD = 0.20 and p<0.01. These results indicate that the DE and ME content of CGF varied substantially but the DE and ME for finishing pigs can be accurately predicted from equations based on nutritional analysis.

The net energy values of corn, dried distillers grains with solubles and wheat bran for laying hens using indirect calorimetry method

The present study was conducted to estimate the NE values of corn, dried distillers grains with solubles (DDGS) and wheat bran (WB) for laying hens based on an indirect calorimetry method and nitrogen balance measurements. A total of 576 twenty-eight-wk-old Dwarf Pink-shell laying hens were randomly assigned to four groups fed a basal diet (BD) or a combination of BD with 50% corn or 20% DDGS or 20% WB, with four replicates each. After a 7-d adaptation period, each replicate with 36 hens were kept in one of the two respiration chambers to measure the heat production (HP) for 6 days during the feeding period and subsequent 3-d fasting. The equilibrium fasting HP (FHP) provided an estimate of NE requirements for maintenance (NEm). The NE values of test feedstuffs was estimated using the difference method. Results showed that the heat increment that contributed 35.34 to 37.85% of ME intake was not influenced by experimental diets (p>0.05) when expressed as Mcal/kg of DM feed intake. Lighting increased the HP in hens in an fed-state. The FHP decreased over time (p<0.05) with the lowest value determined on the third day of starvation. No significant difference between treatments was found on FHP of d 3 (p>0.05). The estimated AME, AMEn, and NE values were 3.46, 3.44 and 2.25 Mcal/kg DM for corn, 3.11, 2.79, and 1.80 Mcal/kg DM for DDGS, 2.14, 2.10, and 1.14 Mcal/kg DM for WB, respectively. The net availability of AME of corn tended to be numerically higher than DDGS and WB (p = 0.096). In conclusion, compared with corn, the energy values of DDGS and WB were overestimated when expressed on an AME basis.

Earlier Metabolizable Energy Intake Level Influences Heat Production during a Following 3-Day Fast in Laying Hens

The present study was conducted to estimate energy requirements for maintenance in laying hens by using indirect calorimetry and energy balance. A total of 576 28-wk-old Nongda-3 laying hens with dwarf gene were randomly allocated into four ME intake levels (86.57, 124.45, 166.63 and 197.20 kcal/kg body weight (BW)(0.75) per d) with four replicates each. After a 4 d adaptation period, 36 hens from one replicate were maintained in one of the two respiration chambers to measure the heat production (HP) for 3 d during the feeding period and subsequent 3 d fast. Metabolizable energy (ME) intake was partitioned between heat increment (HI), HP associated with activity, fasting HP (FHP) and retained energy (RE). The equilibrium FHP may provide an estimate of NE requirements for maintenance (NEm). Results showed that HP, HI and RE in the fed state increased with ME intake level (p<0.05). Based on the regression of HP on ME intake, the estimated ME requirements for maintenance (MEm) was 113.09 kcal/kg BW(0.75) per d when ME intake equals HP. The FHP was decreased day by day with the lowest value on the third day of starvation. Except for lowest ME intake level, the FHP increased with ME intake level on the first day of starvation (p<0.05). The FHP at the two higher ME intake levels were greater than that at the two lower ME intake levels (p<0.05) but no difference was found between the two lower ME intake levels. Linear regression of HP from the fed state to zero ME intake yielded a value of 71.02 kcal/kg BW(0·75) per d, which is higher than the extrapolated FHP at zero ME intake (60.78, 65.23 and 62.14 kcal/kg BW(0.75) per d for the first, second and third day of fasting, respectively). Fasting time, lighting schedules, calculation methods and duration of adaptation of hens to changes in ME intake level should be properly established when using indirect calorimetry technique to estimate dietary NE content, MEm and NEm for laying hens.

Feed energy evaluation for growing pigs

Pigs require energy for maintenance and productive purposes, and an accurate amount of available energy in feeds should be provided according to their energy requirement. Available energy in feeds for pigs has been characterized as DE, ME, or NE by considering sequential energy losses during digestion and metabolism from GE in feeds. Among these energy values, the NE system has been recognized as providing energy values of ingredients and diets that most closely describes the available energy to animals because it takes the heat increment from digestive utilization and metabolism of feeds into account. However, NE values for diets and individual ingredients are moving targets, and therefore, none of the NE systems are able to accurately predict truly available energy in feeds. The DE or ME values for feeds are important for predicting NE values, but depend on the growth stage of pigs (i.e., BW) due to the different abilities of nutrient digestion, especially for dietary fiber. The NE values are also influenced by both environment that affects NE requirement for maintenance (NE_m) and the growth stage of pigs that differs in nutrient utilization (i.e., protein vs. lipid synthesis) in the body. Therefore, the interaction among animals, environment, and feed characteristics should be taken into consideration for advancing feed energy evaluation. A more mechanistic approach has been adopted in Denmark as potential physiological energy (PPE) for feeds, which is based on the theoretical biochemical utilization of energy in feeds for pigs. The PPE values are, therefore, believed to be independent of animals and environment. This review provides an overview over current knowledge on energy utilization and energy evaluation systems in feeds for growing pigs.

Effects of Dietary Fat Types on Growth Performance, Pork Quality, and Gene Expression in Growing-finishing Pigs

This study was performed to determine the effects of dietary fat sources, i.e., beef tallow, soybean oil, olive oil and coconut oil (each 3% in feed), on the growth performance, meat quality and gene expression in growing-finishing pigs. A total of 72 crossbred pigs (Landrace×Large White×Duroc) were used at 71±1 kg body weight (about 130 d of age) in 24 pens (320×150 cm) in a confined pig house (three pigs per pen) with six replicate pens per treatment. The growing diet was given for periods of 14±3 d and the finishing diet was given for periods of 28±3 d. The fat type had no significant effect either on growth performance or on chemical composition or on meat quality in growing-finishing pigs. Dietary fat type affected fatty acid composition, with higher levels of unsaturated fatty acids (UFAs) and monounsaturated fatty acids (MUFAs) in the olive oil group. Microarray analysis in the Longissimus dorsi identified 6 genes, related to insulin signaling pathway, that were differentially expressed among the different feed groups. Real time-PCR was conducted on the six genes in the longissimus dorsi muscle (LM). In particular, the genes encoding the protein kinase, cAMP-dependent, regulatory, type II, alpha (PRKAR2A) and the catalytic subunit of protein phosphatase 1, beta isoform (PPP1CB) showed the highest expression level in the olive oil group (respectively, p<0.05, p<0.001). The results of this study indicate that the type of dietary fat affects fatty acid composition and insulin signaling-related gene expression in the LM of pigs.

Daily feed intake, energy intake, growth rate and measures of dietary energy efficiency of pigs from four sire lines fed diets with high or low metabolizable and net energy concentrations

A trial was conducted to: i) evaluate the BW growth, energy intakes and energetic efficiency of pigs fed high and low density diets from 27 to 141 kg BW, ii) evaluate sire line and sex differences when fed both diets, and iii) to compare ME to NE as predictor of pig performance. The experiment had a replicated factorial arrangement of treatments including four sire lines, two sexes (2,192 barrows and 2,280 gilts), two dietary energy densities and a light or heavy target BW, 118 and 131.5 kg in replicates 1 to 6 and 127 and 140.6 kg in replicates 7 to 10. Pigs were allocated to a series of low energy (LE, 3.27 Mcal ME/kg) corn-soybean meal based diets with 16% wheat midds or high energy diets (HE, 3.53 to 3.55 Mcal ME/kg) with 4.5 to 4.95% choice white grease. All diets contained 6% DDGS. The HE and LE diets of each of the four phases were formulated to have equal lysine:Mcal ME ratios. Pigs were weighed and pen feed intake (11 or 12 pigs/pen) recorded at 28-d intervals. The barrow and gilt daily feed (DFI), ME (MEI) and NE (NEI) intake data were fitted to a Bridges function of BW. The BW data of each sex were fitted to a generalized Michaelis-Menten function of days of age. ME and NE required for maintenance (Mcal/d) were predicted using functions of BW (0.255 and 0.179 BW^0.60 respectively). Pigs fed LE diets had decreased ADG (915 vs. 945 g/d, p<0.001) than pigs fed HE diets. Overall, DFI was greater (p<0.001) for pigs fed the LE diets (2.62 vs. 2.45 kg/d). However, no diet differences were observed for MEI (8.76 vs. 8.78 Mcal/d, p = 0.49) or NEI (6.39 vs. 6.44 Mcal/d, p = 0.13), thereby indicating that the pigs compensated for the decreased energy content of the diet. Overall ADG:DFI (0.362 vs. 0.377) and ADG:Mcal MEI (0.109 vs. 0.113) was less (p<0.001) for pigs fed LE compared to HE diets. Pigs fed HE diets had 3.6% greater ADG:Mcal MEI above maintenance and only 1.3% greater ADG:Mcal NEI (0.152 versus 0.150), therefore NEI is a more accurate predictor of growth and G:F than MEI. Pigs fed HE diets had 3.4% greater ADG:Mcal MEI and 0.11% greater ADG:NEI above maintenance than pigs fed LE diets, again demonstrating that NEI is a better predictor of pig performance than MEI. Pigs fed LE diets had similar daily NEI and MEI but grew slower and less efficiently on both ME and NE basis than pigs fed HE diets. The data suggest that the midds NE value (2.132 Mcal/kg) was too high for this source or that maintenance was increased for pigs fed LE diets.

Nutritional value of full-fat green canola seed fed to growing-finishing pigs

Immature green canola seed (full-fat green canola seed [FFGC]) is rejected by canola crushing plants due to chlorophyll staining of oil destined for human consumption. With >35% oil, FFGC can contribute energy to pig diets. The nutritive value of FFGC for growing-finishing pigs was determined in 2 studies. In Exp. 1, 6 ileal-cannulated barrows (46.5 kg BW) were fed 3 diets as a replicated 3 × 3 Latin square to determine standardized ileal digestible (SID) coefficients of AA and calculate DE and NE values for FFGC. A diet including 40% FFGC replaced wheat in a basal diet and a cornstarch-based N-free diet were fed to determine energy and nutrient digestibility by difference and to estimate basal endogenous AA losses to calculate SID of AA. In Exp. 2, 1,100 pigs (32.9 kg BW), housed in 50 pens of 22 barrows or gilts per pen, were fed 5 diets including 0, 5, 10, and 15% constant or declining amounts (15, 10, 5, 0, and 0%, respectively) of FFGC over 5 phases to determine effects of feeding FFGC on growth performance and carcass characteristics. Phase diets were formulated to provide 4.00, 3.60, 3.25, 2.90, and 2.65 g SID Lys/Mcal NE for d 0 to 21, d 22 to 42, d 43 to 62, d 63 to 74, and d 75 to 123 kg market weight. Carcass characteristics were measured using the Destron grading system. On DM basis, FFGC contained 43% ether extract, 25% CP, 22% NDF, 10 μmol/g glucosinolates, 1.35% Lys, 0.5% Met, 0.9% Thr, and 0.27% Trp. In FFGC, SID coefficients of Lys, Met, Thr, and Trp were 86.9, 87.3, 76.9, and 84.3%, respectively, and calculated DE and NE values were 4.92 and 3.50 Mcal/kg of DM, respectively. Overall, increasing dietary FFGC inclusion from 0 to 15% linearly decreased (P < 0.05) G:F, carcass weight, and dressing percentage (0.392 to 0.381 kg/kg, 96.7 to 95.7 kg, and 78.4 to 77.8%, respectively) and tended to decrease (P = 0.078) ADG. Pigs fed decreasing amounts of FFGC by growth phase compared with controls (0% FFGC) had lower (P = 0.011) overall G:F (0.392 vs. 0.372 kg/kg). Increasing dietary FFGC inclusion did not affect carcass backfat thickness and loin depth. The FFGC was a good source of dietary energy and AA. However, increasing dietary FFGC inclusion for pigs reduced G:F and dressing percentage likely because of the increased dietary fiber content, resulting from increasing FFGC and barley and reducing wheat, soybean meal, and tallow in diets. Inclusion of FFGC in swine diets should, therefore, be based on targeted G:F and relative cost to other feedstuffs.

Effect of experimental methodology on fasting heat production and the net energy content of corn and soybean meal fed to growing pigs

The aim of the three experiments was to evaluated methods to predict fasting heat production (FHP) and to compare methods to determine the net energy (NE) of corn and soybean meal (SBM) fed to growing pigs. To estimate heat production (HP), pigs were housed in respiratory chambers for all experiments. In Experiment 1, six barrows (43.0 ± 1.4 kg body weight [BW]) were fed a Corn-SBM diet for 20 d. The experimental design consisted of following periods: 7 d adaptation, 5 d ad libitum feeding, 3 d feeding at 2 × metabolisable energy (ME) for maintenance (MEm), 3 d feeding at 1 × MEm and 2 d fasting. The FHP was calculated by extrapolating HP measured at the different feeding levels to zero ME intake. The daily FHP [per kg BW(0)(.6)] determined directly after fasting for 24 h and using the regression method was 774 kJ and 694 kJ, respectively. In Experiment 2, 18 barrows (34.3 ± 1.1 kg BW) were randomly allotted to three diets: Diet 1 contained 97.5% corn (direct NE determination of corn); diets 2 and 3 contained 25 % and 15% SBM at the expense of corn, respectively, and were used to calculate the NE of corn by difference. The NE of corn determined directly (13.21 MJ/kg DM) and by difference (13.69 MJ/kg DM) was not different. In Experiment 3, 24 barrows (36.2 ± 1.4 kg BW) were randomly allotted to four diets to determine the effects of different basal diets on the NE content of SBM. The diets were: Basal diet 1 (97.5% corn), Test diet 1 (15% SBM at the expense of corn), Basal diet 2 (contained 72.5% corn and 25% SBM) and Test diet 2 (58% corn and 39.5% SBM). These diets were used to determine the NE of SBM using the Corn-basal diet or the Corn-SBM-basal diet, respectively. It was shown that the estimated NE of SBM did not depend on the used diet (10.04 MJ/kg and 10.62 MJ/kg DM for Basal diet 1 and 2, respectively). In summary, using the regression method to determine FHP results in lower FHP than the fasting method. There was no difference observed in the NE of corn determined directly or by difference, and different basal diets did not affect the NE of SBM.

Performance of piglets in response to the standardized ileal digestible phenylalanine and tyrosine supply in low-protein diets

Reducing the CP level of the diet allows for a reduction in N excretion without limiting performance as long as the amino acid (AA) requirements are covered. The availability of crystalline AA has permitted for a considerable reduction in the CP level of diets, practically used in pig nutrition. The adoption of low CP diets and the extent to which the CP content can be reduced further depends on the knowledge of the minimum levels of indispensable AA that maximize growth. The standardized ileal digestible (SID) Phe : Lys and Tyr : Lys requirements and the possibility to substitute Tyr by Phe have never been studied in piglets. The objectives of this study were to estimate these requirements in 10 to 20 kg pig as well as to determine the extent to which Phe can be used to cover the Tyr requirement. In three dose-response studies, six pigs within each of 14 blocks were assigned to six low CP diets (14.5% CP) sub-limiting in Lys at 1.00% SID. In experiment 1, the SID Phe : Lys requirement estimate was assessed by supplementing a Phe-deficient diet with different levels of l-Phe to attain 33%, 39%, 46%, 52%, 58%, and 65% SID Phe : Lys. Because Phe can be used for Tyr synthesis, the diets provided a sufficient Tyr supply. A similar approach was used in experiment 2 with six levels of l-Tyr supplementation to attain 21%, 27%, 33%, 39%, 45% and 52% SID Tyr : Lys. Phenylalanine was supplied at a level sufficient to sustain maximum growth (estimated in experiment 1). The SID Phe : Lys and SID Tyr : Lys requirements for maximizing daily gain were 54% and 40% using a curvilinear-plateau model, respectively. A 10% deficiency in Phe and Tyr reduced daily gain by 3.0% and 0.7%, respectively. In experiment 3, the effect of the equimolar substitution of dietary SID Tyr by Phe to obtain 50%, 57%, and 64% SID Phe : (Phe+Tyr) was studied at two limiting levels of Phe+Tyr. From 57% to 64% SID Phe : (Phe+Tyr), performance was slightly reduced. In conclusion, it is recommended not to use a Phe+Tyr requirement in the ideal AA profile but rather use a SID Phe : Lys of 54% and a SID Tyr : Lys of 40% to support maximal growth.

Estimation of the net energy requirements for maintenance in growing and finishing pigs

The objective of this experiment was to determine the net energy requirements for maintenance of growing and finishing pigs using regression models. Thirty-six growing (27.38 ± 2.24 kg) and 36 finishing (70.25 ± 2.61 kg) barrows were used and within each phase. Pigs received a corn-soybean meal diet fed at 6 levels of feed intake, which were calculated as 0, 20, 40, 60, 80, or 100% of the estimated ad libitum ME intake (2,400 kJ ME/kg BW(0.6)·d(-1)) of the pigs. Measurements were conducted on 6 pigs per feeding level and per stage of growth. After a 5-d adjustment period, barrows in the fasted treatment were kept in respiration chambers for 2 d to measure the fasting heat production. Barrows in the other treatments were kept individually in respiration chambers for a 5-d balance trial followed by a 2-d fasting period. Heat production (HP) in the fed state was measured and feces and urine were collected in the balance trial. The total HP increased (P < 0.01) with increasing feeding levels. Fasting HP increased (P < 0.01) as previous feeding level increased and was less (P = 0.012) in finishing pigs than growing pigs if calculated per kilogram BW(0.6) per day. When using an exponential regression analysis, ME requirements for maintenance were estimated at 973 and 921 kJ/kg BW(0.6)·d(-1) and NE requirements for maintenance were estimated at 758 and 732 kJ/kg BW(0.6)·d(-1) for growing and finishing pigs, respectively. The efficiencies of using ME for growth and for maintenance were estimated at 66 and 78.7% for growing and finishing pigs, respectively. It is concluded that exponential regression between HP and a wide range of ME intake may be used as a new method to determine the NE requirement for maintenance.