Measurement of endogenous amino acid losses in poultry

Transgenic, high-protein sorghums display promise in poultry diets in an initial comparison

This study aimed to compare the inclusion of transgenic sorghums against commercially available sorghums on growth performance in broiler chickens. Isonitrogenous and isoenergetic diets were offered to a total 288 male Ross 308 broiler chickens from 14 to 35 d posthatch. Three dietary treatments were diets based on transgenic sorghums with a mean protein content of 154.7 g/kg and 5 treatments were based on commercially available sorghum hybrids with a mean protein content of 90.6 g/kg. Soybean meal inclusions in the commercial sorghum diets averaged 215 g/kg, which was reduced to 171 g/kg in the transgenic sorghum diets because of the higher protein contents. Overall growth performance was highly satisfactory, and commercial sorghums supported 2.55% (2,330 vs. 2,272 g/bird; P = 0.010) more weight gains and 2.74% (2,929 vs. 2,851 g/bird; P = 0.012) higher feed intakes; however, the transgenic sorghums supported a fractionally better FCR (1.255 vs 1.257; P = 0.826). There were no statistical differences in apparent jejunal and ileal starch and protein (N) digestibility coefficients between treatments. The transgenic sorghum diets generated slightly, but significantly, higher AME:GE ratios and AMEn, but the commercial sorghum diets generated 6.33% (235 vs. 221 g/kg; P < 0.001) greater breast meat yields. Apparent ileal digestibility coefficients of 16 amino acids averaged 0.839 and 0.832 for transgenic and commercial sorghum-based diets, respectively, without any significant differences in individual amino acids. This outcome suggests amino acid digestibilities of the transgenic sorghums may be inherently higher than commercial hybrid sorghums as the 25.7% higher average soybean meal inclusions would have advantaged amino acid digestibilities in commercial sorghum diets. The possibility that the digestibilities of amino acids in the kafirin component of transgenic sorghums was enhanced by modifications to the structure of kafirin protein bodies is discussed. In conclusion, transgenic sorghums with higher protein concentrations led to 20.5% reduction of soybean meal inclusions in broiler diets, and this change did not compromise feed conversion efficiency compared to standard commercial hybrid sorghums.

Assessment of four different dietary amino acid profiles recommended for ISA Brown layer hens: A validation study

The current feeding study was designed to validate the two dietary essential amino acid profiles (EAAP) established based on linear broken-line (LBL) and quadratic broken-line (QBL) models, in a previous study, against Evonik (AMINOHen) and breeder recommendations for ISA Brown layers for peak production (PP, 20 to 44 weeks of age), and post peak production (post PP, 44 to 75 weeks of age). The EAAP based on LBL models on average had 19.5% and 26.0% lower digestible AA (Lys, Met + Cys, Thr, Trp, Ile and Val), than the EAAP based on QBL models for PP and post PP, respectively. The EAAP based on AMINOHen and breeder recommendation had lower digestible AA than QBL, and higher EAAP than LBL models for both production phases. At 20 weeks of age, 224 ISA Brown layer hens were weighed and randomly allocated to individual battery cages. Each of the four diets was replicated 8 times with 7 birds per replicate. Egg production was recorded daily, and egg weights were measured at the end of each week. Feed consumption was measured at the end of each period. The egg production rate was not significantly affected by the diets and remained at around 98.0% (PP) and 95.0% (post PP) (P > 0.05). Birds fed diets based on LBL recommendation consistently laid smaller eggs, resulting in a lower egg mass (59.8 vs. 62.0 g egg/hen per day during PP, and 60.3 vs. 63.0 g egg/hen per day during post PP; P < 0.05). Diets had no significant effect on feed intake and body weight (P > 0.05). The highest feed conversion ratio (FCR) during PP (P = 0.067) and post PP (P < 0.05) was recorded for the birds offered diets based on LBL recommendation. In conclusion, all four EAAP tested in this study support an above average egg production rate. However, the EAAP based on LBL models may potentially decrease the input feed cost per kilogram of eggs but are not set to optimise FCR and maximise egg mass.

The Chemical Composition of Soyhulls and Their Effect on Amino Acid and Nutrient Digestibility in Laying Hens during the Peak of Production

This study investigates the chemical composition of soyhulls (SHs) as an alternative feed ingredient and their effect on nutrient and amino acid (AA) digestibility in laying hens during peak production. A total of 200 golden brown hens (28 weeks old) were subjected to random allocation across 5 dietary treatments: a corn-soybean meal (SBM) reference diet and 4 test diets with 25% SHs from different mills (SH1, SH2, SH3, and SH4). Each treatment was replicated four times with ten birds per replicate. Digesta samples were collected during three phases (28-32, 32-36, and 36-40 weeks of age) to measure apparent metabolizable energy (AME), the apparent ileal digestibility (AID) of nutrients, and the standard ileal digestibility (SID) of AAs. The SBM diet had 30.0% crude protein (CP) and 3.78% crude fiber (CF), while the SH diets had 21.0 to 21.5% CP and 11.6% CF. The findings revealed that the AME was lower (p < 0.05) with SH diets (2404 kcal/kg) compared to the SBM diet (2627 kcal/kg) in all three phases. The SH diets had a lower AID of dry matter (DM), crude protein (CP), ash, ether extract (EE), and crude fiber (CF) than the SBM diet by an average of 2.88, 2.25, 4.93, 4.99, and 3.36%, respectively. The AID of nitrogen-free extract (NFE) was higher in the SH diets than the SBM diet by 3.42% in all three phases (p < 0.05). The SH diets had lower uric acid excretion (about 66.93 mg/100 mL) than the SBM diet (about 76.43 mg/100 mL) on average in all three phases. The SH diets had a lower SID of arginine, histidine, isoleucine, lysine, cysteine, valine, and tyrosine than the SBM diet by 2 to 10%, while the SID of methionine was higher in the SH diets than the SBM diet by 2.2% on average in all three phases (p < 0.05). The SH from Sadiq Brother Feed (SH1) had the highest AME and AID of DM, ash, CP, EE, CF, and the SID of AA among the SH diets. These results indicate that SH can partially replace SBM in laying hen diets, but the source and quality of SH should be considered.

The influence of dietary crude protein concentrations, grain types and arginine:lysine ratios on the performance of broiler chickens

The objective of this study was to investigate the effects of dietary crude protein (CP) concentrations, grain types and arginine:lysine ratios on performance parameters of broiler chickens. The 2 × 2 × 2 factorial array of dietary treatments harnessed two CP concentrations (210 and 170 g/kg), two feed grains (wheat and sorghum), and two arginine:lysine ratios (104 and 110). Each dietary treatment was offered to 7 replicates of 14 birds per floor pen, a total of 784 off-sex male, Ross 308 broilers, from 14 to 35 d post-hatch. The dietary CP reduction compromised weight gain by 10.0% (2078 versus 2310 g/bird) as a main effect and FCR by 7.51% (1.474 versus 1.371), subject to an interaction. In a three-way interaction (P = 0.008), expanded arginine:lysine ratios improved FCR by 2.30% in 170 g/kg CP, sorghum-based diets but compromised FCR by 2.12% in corresponding wheat-based diets. Sorghum was the more suitable feed grain in reduced-CP diets as sorghum generated significant advantages in weight gain of 7.59% (2154 versus 2002 g/kg) and FCR of 6.94% (1.421 versus 1.527) in birds offered 170 g/kg CP diets. Both dietary CP and feed grain generated significant and divergent impacts in apparent ileal digestibility coefficients for the majority of 16 assessed amino acids. Dietary CP reductions increased non-bound amino acid inclusions (NBAA) in wheat-based diets (48.96 versus 9.80 g/kg) to a greater extent than sorghum-based diets (35.3 versus 9.50 g/kg) and increasing dietary NBAA inclusions were linearly associated with compromised weight gain (r = -0.834; P < 0.001) and FCR (r = 0.862; P < 0.001). Increasing ratios of free arginine to lysine plasma concentrations were linearly (r = -0.466; P = 0.004) related to improvements in FCR. The implications of the observed outcomes are discussed and possible explanations are advanced.

Quantification of secretory IgA and mucin excretion and their contributions to total endogenous amino acid losses in roosters that were fasted or precision-fed a nitrogen-free diet or various highly digestible protein sources

The objective of this study was to quantify total secretory IgA (sIgA) and mucin excretion via excreta in roosters fed diets containing highly digestible protein sources and to determine their proportional contributions to total endogenous amino acid (AA) losses. Precision-fed rooster assays with 24 h excreta collections were conducted using conventional White Leghorn roosters (4-8 roosters per treatment). In Experiment 1, roosters were fasted or precision-fed 30 g (crop intubation) of a nitrogen-free (NF) or semi-purified diet containing 10% casein. Roosters in Experiment 2 received a NF or semi-purified diet containing either 10% casein, 17% whole egg, 10% egg white, 9.8% soy protein isolate, 10.2% chicken breast meat, 11.2% spray-dried animal plasma (SDAP), or an AA mixture containing the same AA as casein. A Latin square design was used in Experiment 3, where roosters received NF or semi-purified diets containing either 10% casein, 17% whole egg, or 9.6% of a crystalline AA mixture to evaluate both diet and individual bird effects. In Experiment 1, mucin excretion did not differ (P > 0.05) among treatments; however, total sIgA excretion was lower for fasted birds, intermediate for the NF diet, and highest for casein (P < 0.05). Total endogenous AA losses (proportion of the total) from sIgA were higher for roosters fed casein, whereas mucin contributions were higher for fasted roosters (P < 0.05). In Experiment 2, sIgA excretion did not differ (P > 0.05) among treatments; however, mucin excretion was reduced for NF, whole egg, egg white, and chicken breast compared with casein and SDAP. In Experiment 3, sIgA and mucin excretion did not differ (P > 0.05) among treatments; however, sIgA excretion differed among individual roosters (7-27 mg/24 h; P < 0.05). Overall, fasting reduced sIgA excretion and sIgA and mucin excretion were affected by dietary protein source. Further, roosters excreted a substantial amount of sIgA, and sIgA and mucin were considerable contributors to total endogenous AA losses.

Assessment of limiting dietary amino acids in broiler chickens offered reduced crude protein diets

As lowering crude protein (CP) in poultry diets continues to minimize amino acid excess, it is important to understand the limiting order of amino acids and the impact of their deficiencies. Therefore, a pair of experiments were conducted to observe the effects of individual amino acid deletions on growth performance, carcass traits, and nutrient utilization. Both experiments involved 3 control diets based on wheat and soybean meal, including a 210.0 g/kg CP industry control (IC), 186.7 g/kg CP positive control (PC) supplemented with feed-grade amino acids to match the IC amino acid profile, 186.7 g/kg CP negative control (NC) with reducing N corrected apparent metabolizable energy (AME_N) by 0.5 MJ/kg and removing feed-grade amino acids beyond L-Lys-HCl, DL-Met, and L-Thr from PC. Ten deletion diets where the following supplemented amino acids were individually removed from the PC: Val, Ile, Leu, Trp, Arg, His, Phe + Tyr, glycine equivalence (Gly_equi), Pro, and Energy (0.5 MJ/kg reduction in AME_N of the PC). All diets were formulated to contain similar concentrations of digestible Lys, total sulfur amino acid (TSAA) and Thr. Experimental diets were offered to broiler chickens from 15 to 22 d post–hatch in a cage study (Exp. 1) to gain digestibility and nutrient utilization data; whereas they were offered from 15 to 35 d post–hatch in a floor-pen study (Exp. 2) to gain performance and carcass yield data. The removal of supplemented Val, Arg, and Ile resulted in reduction on broiler performance (P < 0.05), and the removal of Val, Arg, Ile, and Gly_equi negatively influenced carcass traits (P < 0.05). Results from both experiments indicate that Val and Arg are co-limiting in wheat-soybean meal diets, but that Ile and Gly_equi may potentially limit breast and thigh development.

Dietary crude protein concentrations, feed grains and whey protein interactively influence apparent digestibility coefficients of amino acids, protein, starch and performance of broiler chickens

The present study was designed to investigate the impacts of dietary crude protein (CP) concentrations (220 and 180 g/kg) in either maize- or wheat-based diets, without or with 25 g/kg inclusions of whey powder (WP) concentrate on performance parameters and apparent amino acid digestibility coefficients in broiler chickens. The maize and wheat used in this study had CP levels of 84 and 119 g/kg, respectively. The 2 × 2 × 2 factorial array of 8 dietary treatments was offered to a total of 336 off-sex, male Ross 308 chicks from 7 to 35 d post-hatch with 7 replicate cages (6 birds per cage) per treatment. A treatment interaction (P = 0.016) between dietary CP and feed grains was detected for weight gains, where birds offered 180 g/kg maize-based diets displayed a weight gain advantage of 6.74% (2,628 vs. 2,462 g/bird) compared to their wheat-based counterparts. An interaction (P = 0.022) between feed grains and whey protein was observed for FCR as the addition of WP to maize-based diets improved FCR by 3.45% (1.314 vs. 1.361), but compromised FCR in wheat-based diets by 2.98% (1.415 vs. 1.374). A treatment interaction (P = 0.038) between dietary CP and feed grains was recorded for relative abdominal fat-pad weights weight gains as birds offered 180 g/kg CP maize-based diets had 43.4% (11.17 vs. 7.79 g/kg) heavier fat-pads than their wheat-based counterparts. Following the reduction in dietary-CP, apparent amino acid digestibility coefficients were depressed to greater extents in wheat-based diets. However, significant interactions between CP and feed grains were found in 14 of the 16 amino acids assessed and significant interactions between CP and WP were observed for 15 amino acids. Maize was the more suitable feed grain in terms of weight gain and FCR in 180 g/kg CP diets despite causing greater fat deposition. The inclusion of WP in reduced-CP diets did not enhance bird performance. Data generated indicate concentrations of microbial amino acids in distal ileal digesta were depressing apparent amino acid digestibility coefficients, which was more evident in wheat-based diets. Higher gut viscosities in birds offered wheat-based diets may have facilitated the proliferation of microbiota along the small intestine.

Protein sources and starch-protein digestive dynamics manipulate growth performance in broiler chickens defined by an equilateral-triangle response surface design

A total of 360 male, off-sex Ross 308 chicks were offered 10 dietary treatments from 14 to 35 d post–hatch in an equilateral-triangle response surface design feeding study in order to confirm the importance of protein and amino acid digestive dynamics in broiler chickens. The 3 apical diets were nutritionally-equivalent containing either soybean meal, non-bound amino acids or whey protein concentrate as the major source of dietary protein and amino acids. Appropriate blends of the 3 apical diets comprised the balance of 7 diets and each dietary treatment was offered to 6 replicate cages with 6 birds per cage. Growth performance, nutrient utilisation, apparent protein and starch digestibility coefficients were determined in 4 small intestinal segments. The optimal weight gain (2,085 g/bird) and feed conversion ratios (FCR, 1.397) were generated by Diet 50S50W which included a 50:50 blend of apical diets rich in whey protein concentrate and soybean meal. Broiler chickens offered Diet 50S50W also had the highest experimental and predicted jejunal digestibility (0.685 in proximal jejunum and 0.823 in distal jejunum). FCR was not correlated with apparent distal ileal digestibility coefficient (P > 0.05) of protein but was correlated with apparent protein digestibility in proximal jejunum (r = −0.369, P = 0.040) and distal jejunum (r = −0.316, P = 0.015). Surplus dietary starch was correlated with increased fat pad weight (r = 0.781, P = 0.008). The findings confirmed the relevance of protein digestion rate, reflected by jejunal digestibility, on feed conversion of broiler chickens. A balance between protein-bound and non-bound crystalline or synthetic amino acids may be required for optimal growth and protein digestion.

Productive Performance, Egg Quality and Yolk Lipid Oxidation in Laying Hens Fed Diets including Grape Pomace or Grape Extract

An experiment was conducted to assess in laying hens the effect of including grape pomace (GP, at 30 or 60 g/kg) or grape extract (GE, at 0.5 or 1.0 g/kg) on egg production, feed conversion ratio, protein and polyphenol digestibility, egg weight, egg quality, yolk fatty acid profile and oxidative stability of yolk lipids. No differences were detected among diets for egg production (83.8%, on average) or egg mass (56.8 g/d, on average). However, the average egg weight was lower (p = 0.004) for dietary treatments GP 30, GP 60 and GE 0.5 (67.5 g, on average) than for control hens (68.5 g). Accordingly, in hens fed the GP diets the proportion of XL eggs was lower (p = 0.008) than in control hens, while the proportion of M eggs was higher (p < 0.001) in hens fed the diets GP 30, GP 60 and GE 0.5 than in the control group. The dietary inclusion of both GP and GE decreased daily feed intake (120.9 vs. 125.3 g/d, p < 0.001) and the feed conversion ratio (2.09 vs. 2.18, p = 0.01). Feeding GP at 60 g/kg or GE reduced excreta protein digestibility (54.7 vs. 62.8%, p < 0.001), whereas all GP and GE diets showed higher excreta polyphenol digestibility than the control treatment (57.2 vs. 41.0%, p < 0.001). While yolk colour score was increased with all grape diets (8.12 vs. 7.34, p < 0.001), the dietary inclusion of GP, either at 30 or 60 g/kg, and that of GE at 1.0 g/kg increased the Haugh units of the albumen (80.8 vs. 76.4 Haugh units, p = 0.001). Shell thickness remained unaffected by dietary treatments (365.2 μm, on average). When included in the diet at 60 g/kg, GP reduced the proportion of saturated fatty acids in the yolk (31.6 vs. 32.9%, p = 0.001) and that of monounsaturated fatty acids (39.5 vs. 41.4%, p < 0.001), while it increased the percentage of polyunsaturated fatty acids (28.9 vs. 25.7%, p < 0.001). In fresh eggs, no significant differences were found for the malondialdehyde (MDA) concentration (0.146 mg/kg, on average). In stored eggs, the MDA amount was lower in the eggs of the laying hens fed GP at 60 g/kg than in the eggs of the control hens (1.14 vs. 1.64 mg/kg, p = 0.025). In conclusion, the inclusion of grape pomace, either at 30 or 60 g/kg, and grape extract at 1.0 g/kg in the diet of laying hens improved some egg quality traits, but feeding grape pomace resulted in a lower average weight of eggs. Nevertheless, feeding laying hens with diets containing grape pomace resulted in a higher antioxidant potential in egg yolk than dietary inclusion of grape extract.

A multivariate Box-Behnken assessment of elevated branched-chain amino acid concentrations in reduced crude protein diets offered to male broiler chickens

In a Box-Behnken assessment of elevated branched-chain amino acids (BCAA), 13 nutritionally equivalent maize-based diets were offered to a total of 390 off-sex male Ross 308 broiler chickens from 7 to 28 days post-hatch. The BCAA concentrations investigated in reduced-crude protein diets were 12.5, 15.5, 18.3 g/kg leucine (125, 155, 183); 8.9, 10.2, 12.5 g/kg valine (89, 102, 125) and 7.2, 8.9, 10.8 g/kg isoleucine (72, 89, 109), where their relativity to 11.0 g/kg digestible lysine are shown in parentheses. Determined parameters included growth performance, relative abdominal fat-pad weights, nutrient utilisation, apparent digestibility coefficients, disappearance rates of 16 amino acids and free amino acid systemic plasma concentrations. Increasing dietary leucine linearly depressed weight gain and quadratically influenced FCR where the estimated minimum FCR of 1.418 was with 14.99 g/kg leucine. Polynomial regression analysis and surface response curves of determined parameters were generated for significant (P < 0.05) BCAA variables, based on lack of fit (P > 0.005). Quadratic and cross-product responses were observed for weight gain, FCR, AME, AMEn, N retention and apparent digestibility of 13 amino acids. Relative fat-pad weights declined linearly with increasing isoleucine and valine. The lowest N retention was estimated at a combination of 15.25 and 10.50 g/kg leucine and valine respectively whilst the highest mean digestibility coefficient (0.793) of amino acids was estimated at a combination of 15.74 and 10.47 g/kg of leucine and valine respectively. The remaining parameter minima or maxima responses were not able to be determined since they were outside the extreme BCAA treatment levels. Increasing dietary BCAA significantly increased apparent ileal digestibilities and disappearance rates of BCAA. Systemic plasma concentrations of valine increased (P < 0.001) with increasing dietary valine but leucine was not influenced (P > 0.25). Systemic plasma concentration of isoleucine was maximised (P < 0.001) only when accompanied by elevated dietary leucine. Also, dietary treatments influenced (P < 0.05) apparent disappearance rates of all the essential amino acids analysed, with the exception of methionine. Whilst overall growth performance was not disadvantaged (P > 0.10) by elevated BCAA levels, compared with 2019 Ross 308 performance objectives, polynomial regression analysis suggested both interaction and antagonism between BCAA.

Graded methionine dietary inclusions influence growth performance and apparent ileal amino acid digestibility coefficients and disappearance rates in broiler chickens

Graded quantities of 1.38, 2.76 and 4.14 g/kg L-methionine were included in a control diet formulated to contain 3.07 g/kg digestible methionine. Each of the 4 dietary treatments was offered to 6 replicate cages (initially 8 birds per cage) from 1 to 21 d post-hatch. The parameters assessed included growth performance, nutrient utilisation (apparent metabolisable energy [AME], AME:GE ratios, N retention, N-corrected apparent metabolisable energy [AMEn]), apparent digestibility coefficients and disappearance rates of amino acids in the distal ileum. They also included free amino concentrations in systemic plasma (brachial vein) at 20 d post-hatch and in hepatic tissue at 14 and 21 d post-hatch. Graded L-methionine inclusions quadratically influenced weight gain (r = 0.688; P = 0.001) and FCR (r = 0.780; P < 0.001). It may be deduced from the quadratic regressions that 3.43 g/kg L-methionine supported maximum weight gain of 1,036 g/kg and 3.50 g/kg L-methionine minimum FCR of 1.193, from 1 to 21 d post-hatch. The control diet contained specified levels of 3.07 g/kg digestible methionine and 13.0 g/kg digestible lysine. Thus, an inclusion of 3.465 g/kg L-methionine corresponded to a total of 6.535 g/kg methionine or a methionine-to-lysine ratio of 50.3, which is higher than standard recommendations. The implications of this and other outcomes of the present study are reported and discussed.

Characterisation of undigested components throughout the gastrointestinal tract of broiler chickens fed either a wheat- or maize-based diet

This study was to characterise the undigested nutrients present along the gastrointestinal tract of birds offered common wheat- or maize-based diets, with the goal of optimising utilisation of enzymes to enhance digestive efficiency. Wheat- and maize-based diets were offered to 240 mixed-sex broilers (10 birds/pen; n = 12) from 1 to 35 d post–hatch. Digestibility of dry matter, starch, crude protein and non-starch polysaccharides (NSP) were measured in the crop, gizzard, duodenum, jejunum, ileum, caeca and excreta at d 12 and 35 post–hatch. Analysis of nutrient levels in the excreta presented that more than 30% of nutrients provided in the feed was wasted, irrespective of wheat or maize diet type. On average, 92 g/kg crude protein, 92 g/kg insoluble NSP and 14 g/kg oligosaccharides were not utilised by birds at d 12 post–hatch. The quantity of water-insoluble NSP in the small intestine at d 12 was lower in birds offered the wheat-based diet compared to those fed the maize-based diet (P < 0.05), with the reverse being true for water-soluble NSP (P < 0.001). On average, 84 g/kg crude protein, 79 g/kg insoluble NSP and 9 g/kg oligosaccharides remained in the excreta at 35 d of age. At this time period, accumulation of feed in the gizzard was noted for birds offered both diets, but was more pronounced in those offered the maize-based diet (P < 0.001). Birds offered the maize-based diet demonstrated improved utilisation of oligosaccharides compared to those fed the wheat-based diet at both d 12 and 35 (P = 0.087 and P = 0.047, respectively). Protein utilisation in the jejunum and ileum was greater in birds offered the wheat-based diet compared to those fed the maize-based diet (P = 0.004 and P < 0.001, respectively). Thus, while both diets supported standard growth performance of birds, the degree and flow of nutrient disappearance along the gastrointestinal tract was influenced by cereal type and bird age.

Modeling improvements in ileal digestible amino acids by a novel consensus bacterial 6-phytase variant in broilers

Data from 13 datasets from 4 trials on the effect of a novel consensus bacterial 6-phytase variant (PhyG) on the apparent ileal digestibility (AID) of amino acids (AA) in broilers were used to model AID AA responses. The datasets were obtained from 3 trial locations (New Zealand, Australia and United States) and collectively incorporated variations in diet composition (feedstuff composition, phytate-P (PP) level, limestone solubility), feed form (mash or pellet), bird genetics (strain), and age at sampling (11-35 d of age). In total, 384 observations were analyzed. First, the relationships between AID of AA (as coefficients) and increasing phytase dose level from 0 to 4,000 FTU/kg were evaluated across all datasets using exponential curve fitting. Second, the percentage unit change in AID of AA at each phytase dose level from baseline (basal diet [BD] without phytase) was calculated separately for each dataset and the data then modeled together using exponential curve fitting. The model-predicted mean coefficient of AID of total AA in basal diets was 0.76 (range 0.56 [Cys] to 0.83 [Glu]), which was increased by PhyG to 0.80 and 0.81 at 2,000 and 4,000 FTU/kg, respectively. Exponential increases in the percentage unit improvement in AID of 18 individual and of total AA with increasing phytase dose level were evident (P < 0.05). Improvements (vs. BD) at 2,000 FTU/kg and 4,000 FTU/kg, respectively, were greatest for Cys (+9.2 and +11.0% units), Met (after deduction of synthetic Met, +8.4 and +9.0% units), and Thr (after deduction of synthetic Thr, +6.2 and +7.3% units). The data demonstrated consistent improvements in the AID of AA by the phytase. The modeling results generated from data gathered from birds sampled at different ages and from different dietary settings with correction of synthetic AA for Lys, Met, Thr, and Trp, enabled a more accurate prediction of the digestible AA contribution from the diet by this novel phytase. This will allow diet-specific AA matrix recommendations to be made in commercial feed formulations.

Evaluation of dietary crude protein concentrations, fishmeal, and sorghum inclusions in broiler chickens offered wheat-based diet via Box-Behnken response surface design

The objective of this study was to investigate the impacts of dietary crude protein (CP), fishmeal and sorghum on nutrient utilisation, digestibility coefficients and disappearance rates of starch and protein, amino acid concentrations in systemic plasma and their relevance to growth performance of broiler chickens using the Box-Behnken response surface design. The design consisted of three factors at three levels including dietary CP (190, 210, 230 g/kg), fishmeal (0, 50, 100 g/kg), and sorghum (0, 150, 300 g/kg). A total of 390 male, off-sex Ross 308 chicks were offered experimental diets from 14 to 35 days post-hatch. Growth performance, nutrient utilisation, starch and protein digestibilities and plasma free amino acids were determined. Dietary CP had a negative linear impact on weight gain where the transition from 230 to 190 g/kg CP increased weight gain by 9.43% (1835 versus 2008 g/bird, P = 0.006). Moreover, dietary CP linearly depressed feed intake (r = -0.486. P < 0.001). Fishmeal inclusions had negative linear impacts on weight gain (r = -0.751, P < 0.001) and feed intake (r = -0.495, P < 0.001). There was an interaction between dietary CP and fishmeal for FCR. However, growth performance was not influenced by dietary inclusions of sorghum. Total plasma amino acid concentrations were negatively related to weight gain (r = -0.519, P < 0.0001). The dietary transition from 0 to 100 g/kg fishmeal increased total amino acid concentrations in systemic plasma by 35% (771 versus 1037 μg/mL, P < 0.001). It may be deduced that optimal weight gain (2157 g/bird), optimal feed intake (3330 g/bird) and minimal FCR (1.544) were found in birds offered 190 g/kg CP diets without fishmeal inclusion, irrespective of sorghum inclusions. Both fishmeal and sorghum inclusions did not alter protein and starch digestion rate in broiler chickens; however, moderate reductions in dietary CP could advantage broiler growth performance.

Effect of increasing dose level of a novel consensus bacterial 6-phytase variant on phytate degradation in broilers fed diets containing varied phytate levels

1. The effect of increasing the dose level of a novel consensus bacterial 6-phytase variant on apparent ileal digestibility (AID) of phosphorus (P), phytic acid (inositol hexa-phosphate, IP₆) and ileal IP₆ degradation profile was studied in diets containing varying phytate-P (PP) levels.2. Ross 308, one-day-old males (n=1,800) were allocated to cages (20 birds/cage, six cages/treatment) in a completely randomised design employing a 3 × 5 factorial arrangement (three PP levels: 2.45 (low) 2.95 (medium) and 3.45 g/kg (high); five dose levels of phytase (PhyG): 0, 500, 1,000, 2,000 and 4,000 FTU/kg). Phased diets were based on wheat, corn, soybean meal, rapeseed meal and rice bran (d 0 to 10; 2.60 g/kg digestible P, 7.6 g/kg calcium (Ca); d 11 to 21; 2.10 g/kg digestible P, 6.4 g/kg Ca). Ileal digesta was collected on d 21 for determination of P, IP₆ and IP-esters content. Data were analysed by factorial ANOVA; means separation was achieved using Tukey's HSD test.3. Increasing PP reduced AID of IP₆ and sum of IP_3-6 (%) (P<0.05) but absolute P-release (g/kg diet) above NC was increased (P<0.05) at high vs. low PP. Increasing phytase dose exponentially increased (P<0.001) AID IP_6, sum of IP_3-6 (%) and digestible IP_3-6-P g/kg diet (P<0.001). AID P was increased but there was an interaction with PP level (P<0.001). Ileal accumulation of IP_5-3-P was universally low with PhyG at ≥1,000 FTU/kg (<0.06 g/100g DM). At 2,000 and 4,000 FTU/kg, AID IP₆ was 97.2, 92.7, 92.6% and 100, 97.2, 97.1%, respectively, at low, medium and high PP. At 2,000 FTU/kg, phytate-P release estimated as the increase (above NC) in ileal digestible sum of IP_3-6-P in the diet was 2.26, 2.59 and 3.10 g/kg in low, medium and high PP, respectively.4. The data demonstrated that the novel phytase was effective in breaking down phytate to low IP-esters in diets with varied PP content but the optimal dose level for maximising P-release may differ in diets with varying PP content.

Combining Grape Byproducts to Maximise Biological Activity of Polyphenols in Chickens

Simple Summary

Grape byproducts (grape pomace, seeds and skins) contain a wide range of phenolic compounds with antioxidant properties and thus can become functional ingredients in animal feeds. The dietary inclusion of grape pomace in chicken diets has been shown to increase plasma and meat α-tocopherol content and to mitigate meat lipid oxidation. However, the separate inclusion of the main components of grape pomace (grape seeds and skins) in the diet of chickens has been less studied. In the present research work, the dietary inclusion of grape byproducts did not compromise the growth of chickens nor did it affect ileal protein digestibility. Concerning plasma and meat α-tocopherol concentrations and meat lipid oxidation, the dietary combination of grape seeds and skins provided better results than the individual inclusion of these grape byproducts. Actually, combinations with a proportion of at least 50% of grape skins enabled optimal results of meat oxidative stability.

Abstract

Grape seeds (GS) and grape skins (GK) are natural sources of polyphenols with antioxidant capacity. An experiment was conducted to investigate in chickens the effect of including GS and GK (40 g/kg), individually or combined in different proportions (20 g/kg GS–20 g/kg GK; 30 g/kg GS–10 g/kg GK; 10 g/kg GS–30 g/kg GK), in a corn-soybean diet on growth performance, ileal and excreta contents of total extractable polyphenols (TEP) and tannins, ileal digestibility of protein, plasma and meat α-tocopherol concentration and lipid oxidation (assessed by measuring the thiobarbituric acid reactive substances, TBARS) of stored thigh meat. Neither growth performance parameters nor ileal digestibility of protein were affected by dietary treatments. As compared with control birds, chickens fed the grape byproduct diets showed higher ileal (p < 0.001) and excreta (p < 0.001) TEP and tannins contents. Dietary inclusion of grape byproducts increased α-tocopherol concentration both in plasma (p < 0.001) and in thigh meat (p < 0.01 at 1 d; p < 0.001 at 7 d), as compared with the control group. The highest plasma α-tocopherol concentrations were reached with the 30 g/kg GS–10 g/kg GK and 20 g/kg GS–20 g/kg GK combinations. On day 1 of meat storage, no differences on meat α-tocopherol concentration were found among the grape byproducts treatments but on day 7 of storage, the 20 g/kg GS–20 g/kg GK and 10 g/kg GS–30 g/kg GK combinations led to the highest α-tocopherol concentrations in chicken thigh meat. After seven days of refrigerated storage of meat, the TBARS value was lower in chickens fed the grape byproducts diets than in control birds (1.27 vs. 2.49 mg MDA/kg, p < 0.001). Moreover, among the different grape byproduct treatments, the lowest MDA values were reached with the diets containing GK at rates from 20 to 40 g/kg. In conclusion, dietary incorporation of 40 g/kg of GS and GK added separately or combined increased the plasma and meat α-tocopherol content. Furthermore, the combinations of GS and GK with a proportion of GK of at least 50% optimised α-tocopherol concentration both in plasma and in thigh meat and mitigated lipid oxidation in 7-day stored meat.

Evaluating endogenous loss and standard ileal digestibility of amino acids in response to the graded severity levels of E. maxima infection

The study was conducted to evaluate the effects of graded levels of Eimeria maxima challenge on endogenous loss, apparent ileal digestibility (AID), and standard ileal digestibility (SID) of amino acids. A total of 768 fourteen-day-old male Cobb 500 broiler chickens were randomly allocated into 64 battery cages. Apart from the regular corn-soybean based diet, the nitrogen-free diet (NFD) was formulated to determine the endogenous loss of amino acids. One-half of the birds (32 cages) were fed the NFD, and another half fed the regular diet from d 14 to 20. Both groups were further assigned to 4 treatments (nonchallenged control or three levels of challenge doses) with 8 replicate cages. The challenge doses were: the low challenge dose (Low) with E. maxima 12,500 oocysts, the medium challenge dose (Medium) with 25,000 E. maxima oocysts, and the high challenge dose (High) with 50,000 E. maxima oocysts. At 6 d postinfection, ileal digesta samples were collected and the intestinal lesion score were recorded. The results indicated a significant linear increase of endogenous amino acid flow in response to the graded E. maxima challenge. Moreover, the AID and SID of amino acids were linearly reduced due to the increasing challenge dose. The study demonstrated that NFD significantly reduced lesion scores, underestimating the true endogenous losses of birds fed regular diets. Even though the endogenous loss of amino acids was underestimated, they were linearly increased in response to the graded E. maxima challenge. In conclusion, the higher Eimeria dose birds were challenged with, the more endogenous amino acids were released into the intestine and the lower dietary nutrients were digested and absorbed by broiler chickens.

Effects of different feeding regimens with protease supplementation on growth, amino acid digestibility, economic efficiency, blood biochemical parameters, and intestinal histology in broiler chickens

Background

This study was conducted to estimate the impacts of using varied feeding regimens with or without protease supplementation on the growth performance, apparent amino acid ileal digestibility (AID%), economic efficiency, intestinal histology, and blood biochemical parameters of broiler chickens. Three hundred one-day-old chicks (Ross 308 broiler) were randomly allotted to a 3 × 2 factorial design. The experimental design consisted of three feeding regimens; FR1: a recommended protein SBM diet, FR2: a low-protein SBM diet, and FR3: a low-protein diet with the inclusion of 5% DDGS and 5% SFM, with or without protease supplementation (250 mg/kg).

Results

Increased feed intake and feed conversion ratio were observed in the FR3 treatment during the starter stage and decreased body weight and body weight gain during the grower stage. However, there was no significant effect of the different feeding regimens, protease supplementation, or interaction on the overall performance. The economic value of diets also remained unaffected by the different feeding regimens, protease supplementation, or interaction. Protease supplementation resulted in lowering the AID% of tryptophan and leucine. Reduced AID% of methionine was evident in the FR2 + VE and FR3 − VE treatments. Histological findings substantiated the FR3 treatment mediated a decrease in the duodenal and jejunal villous height (VH), jejunal villous width (VW), and ileal VW, whereas, increase in the ileal crypt depth (CD). The FR2 + VE treatment reduced the VH:CD ratio in the duodenum. The duodenal CD and the jejunal goblet cell count were reduced as a consequence of protease supplementation. The FR3 + VE treatment documented a rise in duodenal CD, while an increase in the jejunal goblet cell count was observed in the FR3 − VE treatment. The FR3 treatment enhanced the IgM serum levels compared to the FR1 and FR2 treatments. IgM serum levels were also elevated following protease supplementation. FR3 + VE treatment increased IgM serum levels. The highest serum ALP was found in the FR3 treatment, whereas the lowest level was obtained in the FR2 treatment.

Conclusion

Low-protein SBM-based diets could be used without affecting the birds’ growth. Altered morphometric measures of the intestine and increased IgM and ALP levels indicated the low-protein SBM/DDGS-SFM diet-induced damage of the intestinal histoarchitecture and immune system of birds. These different diets and protease supplementation failed to affect economic efficiency positively.

Comparison of methodologies to determine the apparent ileal amino acid digestibility of maize, wheat, lupins, and peas for broiler chickens

The influence of method (direct vs difference method) used to determine the apparent ileal digestibility coefficient (AIDC) of amino acids in two cereals (maize and wheat) and two grain legumes (Australian sweet lupins and peas) was investigated. For the direct method, the test ingredients were incorporated as the sole source of protein in assay diets. The assay diets used in the difference method were formulated by substituting the cereals and legumes for 50 and 25% (w/w), respectively, of a maize-soy basal diet. Each diet contained 3 g/kg titanium dioxide as an indigestible marker and were offered ad libitum to four replicate cages of broilers (four birds/cage) from d 28 to d 35 post-hatching. On d 35, digesta were collected from the terminal ileum and the AIDC of amino acids were calculated using marker ratios in the diet and digesta. Except for histidine, methionine, cysteine and tyrosine, the main effect of methods was found to be significant (P<0.05 to 0.001) for the AIDC of all amino acids. The main effect of the ingredients was significant (P<0.05 to 0.001) for all amino acids, except for histidine, aspartic acid and serine. Interactions (P<0.05) between ingredients and method were observed only for leucine, lysine, proline and serine. The AIDC of amino acids, determined by the difference method, was found to be distinctly higher than those determined by the direct method. This suggested that the direct method underestimated amino acid digestibility in low and medium protein ingredients.

Feeding Broiler Chickens with Grape Seed and Skin Meals to Enhance α- and γ-Tocopherol Content and Meat Oxidative Stability

Grape seeds (GS) and grape skins (GK) are natural sources of polyphenols with featured antioxidant capacity. An experiment was conducted to investigate the effect of these polyphenol sources in diets formulated to contain the same total extractable grape polyphenol content on growth performance, protein and extractable polyphenol digestibility, plasma and meat α- and γ-tocopherol and thigh meat oxidation in broiler chickens. Five experimental diets were formulated: control, control + vitamin E (200 mg/kg), 30 g/kg GS diet, 110 g/kg GK diet, GS + GK diet (a mixture of 24.4 g/kg GS and 13.1 g/kg GK designed to simulate a reconstituted grape pomace). Feeding chickens with 110 g/kg GK reduced (p < 0.001) daily weight gain, worsened (p < 0.001) feed conversion ratio, increased (p < 0.001) non-extractable polyphenol content in the ileum and in the excreta and decreased (p < 0.05) ileal protein digestibility. Regardless of the grape polyphenol source used, the inclusion of grape byproducts in the diets led to an increase of total extractable polyphenol contents in the ileum (p < 0.01) and the excreta (p < 0.001), which resulted (p < 0.001) in a decrease of extractable polyphenol digestibilities. Alpha- and gamma-tocopherol concentrations increased (p < 0.001) in plasma and in seven-day stored meat in birds fed the diet combining GS and GK with respect to the control group. As it happened with the vitamin E supplementation, feeding the combination of GS and GK also reduced (p < 0.001) the concentration of the lipid peroxidation marker (malondialdehyde) in the stored meat of chickens.

Starch digestion rates in multiple samples of commonly used feed grains in diets for broiler chickens

In this study the starch digestion rates in broiler chickens from 18 samples of 5 commonly used feed grains (sorghum, wheat, maize, barley, triticale) were determined. The methodology to determine starch digestion rates in poultry is detailed herein. Starch digestion rates were not significantly different (P = 0.128) across the 18 feed grains, which reflects the wide variations that were observed within a given feedstuff. Nevertheless, starch digestion rates in broiler chickens offered wheat-based diets were significantly more rapid by 56.0% (0.117 versus 0.075 min⁻¹; P = 0.012) than their sorghum-based counterparts on the basis of a pair-wise comparison. In descending order, the following starch digestion rates were observed: wheat (0.117 min⁻¹), barley (0.104 min⁻¹), triticale (0.093 min⁻¹), maize (0.086 min⁻¹), sorghum (0.075 min⁻¹). The implications of these findings are discussed as they almost certainly have implications for poultry nutrition and the development of reduced crude protein diets for broiler chickens.

Changes in the growth, ileal digestibility, intestinal histology, behavior, fatty acid composition of the breast muscles, and blood biochemical parameters of broiler chickens by dietary inclusion of safflower oil and vitamin C

BACKGROUND

The effects of safflower oil and vitamin C (Vit. C) inclusion in broiler chicken diets on the growth performance, apparent ileal digestibility coefficient "AID%" of amino acids, intestinal histology, behavior, carcass traits, fatty acid composition of the breast muscle, antioxidant and immune status for a 35-day feeding period were evaluated. A total of 300 three-day-old Ross chicks (58.25 g ± 0.19) were randomly allotted in a 2 × 3 factorial design consisting of two levels of vitamin C (0 and 400 mg/kg diet) and three levels of safflower oil (0, 5, and 10 g/kg diet).

RESULTS

An increase in the final body weight, total body weight gain, total feed intake, and the relative growth rate (P <  0.05) were reported by safflower oil and vitamin C inclusion. Dietary supplementation of safflower oil and vitamin C had a positive effect (P <  0.05) on the ingestive, resting, and feather preening behavior. Vitamin C supplementation increased (P <  0.05) the AID% of lysine, threonine, tryptophan, arginine, and valine. Safflower inclusion (10 g/kg) increased (P <  0.05) the AID% of methionine and isoleucine. Safflower oil inclusion increased (P <  0.05) the levels of stearic acid, linoleic acid, saturated fatty acids, and omega-3 fatty acids (ω-3) in the breast muscle. In contrast, the supplementation of only 10 g of safflower oil/kg diet increased (P = 0.01) the omega-3/omega-6 (ω-3/ω-6) fatty acids ratio. Vit. C supplementation increased (P <  0.05) the CAT serum levels, SOD, and GSH enzymes. Dietary supplementation of safflower oil and vitamin C improved the intestinal histology. They increased the villous height and width, crypt depth, villous height/crypt depth ratio, mucosal thickness, goblet cell count, and intra-epithelium lymphocytic lick cell infiltrations. The serum levels of IgA and complement C3 were increased (P <  0.01) by Vit. C supplementation and prominent in the 400 vit. C +  10 safflower Oil group.

CONCLUSION

A dietary combination of safflower oil and vitamin C resulted in improved growth rate, amino acids AID%, intestinal histology, welfare, immune and antioxidant status of birds, and obtaining ω-3 and linoleic acid-enriched breast muscles. The best inclusion level was 400 vit. C +  10 safflower Oil.

Effect of Dietary Medium-Chain α-Monoglycerides on the Growth Performance, Intestinal Histomorphology, Amino Acid Digestibility, and Broiler Chickens' Blood Biochemical Parameters

Simple Summary

The addition of biologically active materials to animal feed is a very recent topic regarding antibiotic alternatives. This study inspected the influence of graded levels of medium-chain α-monoglycerides, glycerol monolaurate (GML) on the growth performance, apparent ileal digestibility coefficient (AID%) of amino acids, and intestinal histomorphology of broiler chickens. Broiler chickens (76.82 g ± 0.40, n = 200) were fed on four experimental diets that were complemented with 0; 1; 3; or 5 g kg⁻¹ glycerol monolaurate (GML0; GML1; GML3; and GML5). The findings suggested that glycerol monolaurate supplementation can improve the immune status and intestinal histomorphology of broiler chickens with no improving effect on the growth performance.

Abstract

This trial was conducted to assess the impact of medium-chain α-monoglycerides, glycerol monolaurate (GML) supplementation on the growth performance, apparent ileal digestibility coefficient (AID%) of amino acids, intestinal histomorphology, and blood biochemical parameters of broiler chickens. Three-day-old chicks (76.82 g ± 0.40, n = 200) were haphazardly allocated to four experimental groups with five replicates for each (10 chicks/replicate). The treatments consisted of basal diets supplemented with four glycerol monolaurate levels; 0, 1, 3, or 5 g kg⁻¹ (GML0, GML1, GML3, and GML5, respectively). Growth performance was determined at three periods (starter, grower, and finisher). Dietary GML had no significant effect on the growth performance parameters (body weight, weight gain, and feed conversion ratio) through all the experimental periods. GML1 diet increased the AID% of leucine and decreased the AID% of arginine. GML1 diet increased the duodenal and jejunal villous height and the jejunal muscle thickness. GML3 and GML5 diets increased the goblet cell count in the duodenum. GML supplementation increased the serum level of high density lipoprotein (HDL)-cholesterol. GML5 diet increased the serum levels of IgM and interleukin 10 compared to the control group. We could conclude that dietary supplementation of glycerol monolaurate can supplement broiler chicken diets up to 5 g kg⁻¹ to enhance the immune status and intestinal histomorphology of birds with no improving effect on growth performance.

Effects of Phenolic-Rich Onion (Allium cepa L.) Extract on the Growth Performance, Behavior, Intestinal Histology, Amino Acid Digestibility, Antioxidant Activity, and the Immune Status of Broiler Chickens

The effect of phenolic-rich onion extract (PROE), as a feed additive, was evaluated on the growth, carcass traits, behavior, welfare, intestinal histology, amino acid ileal digestibility "AID%," and the immune status of broiler chicks for 35 days. A total number of 400, 1-day-old broiler chicks (45.38 g ± 1.35) were allocated to four different treatments with 10 replicates each (100 chicks/treatment) consisting of: T1, basal diet without additives (control treatment) (PROE0); T2, basal diet + phenolic-rich onion extract (1 g/kg diet) (PROE1); T3, basal diet + phenolic-rich onion extract (2 g/kg diet) (PROE2); and T4, basal diet + phenolic-rich onion extract (3 g/kg diet) (PROE3). An increase in the final body weight "FBW," bodyweight gain "BWG," and feed consumption was observed (P < 0.05) at different PROE levels. Also, the thymus and bursa percentages were increased in the PROE2 and PROE3 treatments (P < 0.05). The chicks fed on PROE supplemented diets had increased frequency of feeding and drinking and showed comfortable behavior (P < 0.05) with lesser aggression (P < 0.05). Additionally, an increase was observed in the antioxidant enzyme activity, phagocytic %, phagocytic index, and serum lysozyme activity in PROE supplemented treatments, with the best outcome reported in the PROE3 treatment (P < 0.01). IgM was increased in the birds fed with PROE2 and PROE3 diets (P < 0.01). PROE supplementation increased the AID% of lysine and methionine (P <0.01), PROE3 treatment increased the AID% of threonine (P < 0.05), and PROE2 and PROE3 treatments increased the AID% of leucine and isoleucine (P < 0.05). Besides, PROE2, and PROE3 treatments increased the villus height and width, mucosal thickness, and goblet cell count from the duodena, jejuna, and ilea (P < 0.05) compared to control treatment. Based on these results, we concluded that the dietary addition of phenolic-rich onion extracts can improve the growth rate of broiler chicken by improving the AID% of amino acids and intestinal histology. Also, it can improve the welfare, antioxidant enzymes activity, and immune status of the birds. Phenolic-rich onion extracts can be used as a natural growth promoter in the poultry feed for good health and improved performance.

Initial assessment of protein and amino acid digestive dynamics in protein-rich feedstuffs for broiler chickens

A study evaluating apparent digestibilities of protein and amino acids and their corresponding digestion rates in four small intestinal sites in broiler chickens was completed to further investigate dietary optimisation via synchronised nutrient digestion and absorption. A total of 288 male Ross 308 broiler chickens were offered semi-purified diets with eight protein-rich feedstuffs, including; blood meal (BM), plasma protein meal (PPM), cold pressed (CCM) and expeller-pressed (ECM) canola meal, high (SBM HCP) and low (SBM LCP) crude protein soybean meals, lupins and peas. Diets were iso-caloric, iso-nitrogenous and the test ingredient was the sole source of dietary nitrogen. Each diet was offered to 6 bioassay cages with 6 birds per cage from day 21 to 28 post hatch. On day 28, all birds were euthanized and digesta samples were collected from the proximal jejunum, distal jejunum, proximal ileum and distal ileum to determine apparent protein and amino acids digestibility coefficients, digestion rates and potential digestible protein and amino acids. Dietary protein source significantly influenced energy utilisation, nitrogen retention, apparent protein (N) digestibilities, digestion rates and potential digestible protein along the small intestine. Diets containing BM and SBM LCP exhibited the highest protein digestion rate and potential digestible protein, respectively. Digestibility coefficients and disappearance rates of the majority of amino acids in four sections of the small intestine were influenced by dietary protein source (P < 0.01) and blood meal had the fastest protein digestion rate. In general, jejunal amino acid and protein digestibilities were more variable in comparison to ileal digestibilities, and the differences in protein and amino acid disappearance rates were more pronounced between types of feedstuffs than sources of similar feedstuffs.

Protein digestive dynamics of meat and bone meals in broiler chickens

This study determined the variations in protein digestibilities and digestion rates in broiler chickens offered diets containing 7 different meat and bone meals (MBM). A total of 252 male Ross 308 broiler chickens were offered 7 atypical diets largely based on maize and MBM from 24 to 28 d post-hatch. Each experimental diet was offered to 6 replicates with 6 birds per replicate cage. Excreta were collected in their entirety from 25 to 27 d post-hatch and on 28 d post-hatch. Digesta samples were collected from the proximal jejunum, distal jejunum, proximal ileum and distal ileum. Apparent digestibilities of protein were determined in each segment and apparent digestibilities of amino acids were measured in the distal ileum. There were significant differences in apparent protein digestibility coefficients in the proximal jejunum (P = 0.006), where broiler chickens offered the high ash beef meal (diet 7) generated the lowest protein digestibility in the proximal jejunum (0.318). Similarly, there were significant differences in apparent digestibility coefficients in the distal jejunum (P < 0.001) and distal ileum (P < 0.001) but not in the proximal ileum. More pronounced differences were found in the disappearance rate of protein and there were significant differences in all 4 segments of the small intestine (P < 0.001). Broiler chickens offered the high ash beef meal had the lowest protein disappearance rate (P < 0.001). No difference was observed in the predicted protein digestion rate (P = 0.486) but chickens offered the high ash beef meal had the lowest potential digestible protein (0.662, P = 0.034) whereas the highest potential digestible protein (0.739) was detected in diet 5 (containing a beef meal). This study contributed to the establishment of a preliminary database to include digestion rates of starch and protein into practical diet formulation.

Toward standardized amino acid matrices for exogenous phytase and protease in corn-soybean meal-based diets for broilers

A total of 468 male Ross 308 broilers were used in a digestibility study to determine the additivity of apparent or standardized amino acid (AA) digestibility values for corn, soybean meal (SBM), or a mixture of corn and SBM that were supplemented, or not, with either phytase, protease, or a combination of phytase and protease. These treatments generated a total of 12 experimental diets that were arranged in a 3 × 4 design. A nitrogen-free diet was also fed to estimate endogenous AA loss. Apparent and standardized AA digestibility values were assessed on day 28 posthatch. The apparent digestibility of AA in the complete diet was higher (P < 0.05) than expected based on the digestibility of the corn and SBM individually. However, this overestimation was corrected by the adjustment to standardized values. Importantly, addition of protease or the combination of protease and phytase increased (P < 0.05) the digestibility of AA in corn and SBM. Furthermore, these effects were arithmetically coherent with respect to the measured effects of the enzymes in the mixture of corn and SBM, even improving the additivity of AA digestibility values when assessed on an apparent basis. This study demonstrates that the effect of exogenous protease and phytase on AA digestibility in complete diets is predictable based on measurements made in individual ingredients. In addition to improving digestibility values per se, exogenous protease and phytase may enhance precision in least cost formulation systems.

Effect of dietary supplementation of alpha-galactosidase on the growth performance, ileal digestibility, intestinal morphology, and biochemical parameters in broiler chickens

BACKGROUND

This study was performed to investigate the effect of Alpha-galactosidase (AlphaGal) supplementation with two energy levels on the growth performance, amino acid ileal digestibility coefficient "AID%," economic value, intestinal histology, and blood biochemical parameters of broiler chickens. Two-hundred 3-day-old broiler chicks (average body weight 74.34 g ±0.52 Ross 308) were randomly assigned to a 2 × 2 factorial arrangement consisting of two energy diets groups: in the first group, the birds were fed on a recommended energy diet (RED) while the second group was reduced 120 kcal/kg diet as a low energy diet (LED) and two levels of AlphaGal (0 or 50 mg/kg diet) for RED and LED for the 35-day feeding period.

RESULTS

The interaction effects between the energy level and the AlphaGal supplementations resulted in significant decrease (P ≤ 0.05) in the body weight, body weight gain, and the relative growth rate. The feed conversion ratio was signficantly increased in LED without supplementation of AlphaGal group during the entire experimental period, this negative effect on the growth performance was corrected by AlphaGal supplementation. The AID% value was increased significantly by AlphaGal supplementation. Blood triglyceride concentrations were significantly decreased (P = 0.02) in the LED group with or without AlphaGal supplementation, while the level of high-density lipoprotein (HDL) was significantly decreased (P = 0.01) in the LED or RED groups supplemented with 50 mg RED AlphaGal. Histologically, the number of intestinal glands and goblet cells increased in both RED and LED groups supplemented with AlphaGal and their secretions were mainly neutral mucopolysaccharides and less acidic mucopolysaccharides.

CONCLUSION

AlphaGal supplementation improved the growth performance of broiler chickens fed LED and the growth performance is similar to those fed RED, thereby consequently improving the economic value of these diets. AlphaGal supplementation improves intestinal histology and morphology as well.

Capping dietary starch:protein ratios in moderately reduced crude protein, wheat-based diets showed promise but further reductions generated inferior growth performance in broiler chickens

The hypothesis that capping dietary starch:protein ratios would enhance the performance of broiler chickens offered reduced-crude protein (CP) diets was tested in this experiment. A total of 432 off-sex, male Ross 308 chicks were allocated to 7 dietary treatments from 7 to 35 d post-hatch. The experimental design consisted of a 3 × 2 factorial array of treatments with the seventh treatment serving as a positive control. Three levels of dietary CP (197.5, 180.0 and 162.5 g/kg) with either uncapped or capped dietary starch:protein ratios constituted the factorial array of treatments, whilst the positive control diet contained 215.0 g/kg CP. The positive control diet had an analysed dietary starch:protein ratio of 1.50 as opposed to a ratio of 1.68 in the uncapped 197.5 g/kg CP diet and 1.41 in the corresponding capped diet and the capped 197.5 g/kg CP diet displayed promise. The growth performance this diet matched the positive control but outperformed the uncapped 197.5 g/kg CP diet by 10.4% (2,161 vs. 1,958; P = 0.009) in weight gain, by 3.10% (3,492 vs. 3,387; P = 0.019) in feed intake on the basis of pair-wise comparisons and numerically improved FCR by 4.04% (1.616 vs. 1.684). However, the growth performance of birds offered the 180.0 and 162.5 g/kg CP dietary treatments was remarkably inferior, irrespective of dietary starch:protein ratios. This inferior growth performance was associated with poor feathering and even feather-pecking and significant linear relationships between feather scores and parameters of growth performance were observed. The amino acid profile of feathers was determined where cysteine, glutamic acid, glycine, proline and serine were dominant in a crude protein content of 931 g/kg. Presumably, the feathering issues observed were manifestations of amino acid inadequacies or imbalances in the more reduced-CP diets and consideration is given to the implications of these outcomes.

Studies on the measurement of ileal calcium digestibility of calcium sources in broiler chickens

Results from 3 experiments relating to the measurement of ileal calcium (Ca) digestibility in 4 different Ca sources for broiler chickens are presented herein. The first experiment was conducted to determine the effect of basal diet composition on the true Ca digestibility of limestone, meat and bone meal (MBM), monocalcium phosphate (MCP), and dicalcium phosphate (DCP). Eight experimental diets were developed based on 2 basal diets (corn-based or corn starch-based) with each of the 4 Ca sources. Two Ca-free diets representing both basal diets were used to determine the endogenous Ca losses. Each diet was randomly allotted to 6 replicate cages (6 birds per cage) and fed from 21 to 24 D post-hatch. Calcium digestibility of corn-based diet was higher (P < 0.05) than the corn starch-based purified diet. The average true Ca digestibility coefficients of limestone, MBM, MCP, and DCP were determined to be 0.51, 0.41, 0.43, and 0.32, respectively. The second experiment was conducted to examine the effect of indicator type on the apparent Ca digestibility of limestone. Two experimental diets with either titanium dioxide or acid insoluble ash (Celite) were developed. Each diet was randomly allotted to 6 replicate cages (8 birds per cage) and fed from 21 to 24 D post-hatch. Total tract Ca retention was also measured using the indicator ratios. Indicator type had no influence (P > 0.05) on the digestibility measurements. Ca retention determined using acid insoluble ash was higher (P < 0.05) compared to that determined using titanium dioxide. The third experiment was conducted to determine the effect of dietary adaptation length on apparent Ca digestibility of limestone. The experimental diet was offered from day 21 to 6 replicates (6 birds per cage) each for 24, 72, 120, or 168 h and the ileal digesta were collected. Calcium digestibility at 24 h was higher (P < 0.05), and increasing the adaptation length from 72 to 120 h had no effect (P > 0.05) on the digestibility.

Impacts of reduced-crude protein diets on key parameters in male broiler chickens offered maize-based diets

A total of 294 male, off-sex Ross 308 chickens were offered 7 dietary treatments with crude protein (CP) contents of 210, 195, 180, and 165 g/kg. One of the four 165 g/kg diet was consistent with the higher protein diets and 3 were modified to investigate the effects of increased methionine levels, pre-pellet inclusion of whole maize, and whey protein concentrate in reduced-CP broiler diets. There were 7 replicate cages, 6 birds per cage, from 14 to 35 D post-hatch. The average feed conversion ratio (FCR) of birds offered 210, 195, 180 g/kg CP diets was 1.555 which was superior (P < 0.05) to the 1.608 FCR of their 165 g/kg counterparts. The transition from 210 to 165 g/kg (diet 4) CP diets linearly increased (P < 0.001) relative fat-pad weights from 8.64 to 14.62 g/kg. The same transition linearly increased jejunal and ileal starch digestibility coefficients (P < 0.001), metabolizable to gross energy ratios (ME:GE) ratios (P < 0.001) and nitrogen (N)-corrected apparent metabolizable energy (AMEn) (P = 0.001) but did not influence N retention. Starch:protein disappearance rate ratios increased linearly (P < 0.001) from 2.68 to 3.82 in the jejunum and from 1.76 to 2.94 in the ileum following dietary CP reductions. Ileal disappearance rate ratios were quadratically related to FCR (r = 0.486; P < 0.005) and linearly related to relative fat-pad weights (r = 0.663; P < 0.001) where both parameters were disadvantaged by widening ratios. The transition from 210 to 165 g/kg crude protein diets linearly increased the average digestibility coefficient of 17 amino acids from 0.459 to 0.594 in jejunum and from 0.744 to 0.790 in the ileum. The present study demonstrates that dietary CP can be reduced from 210 to 180 g/kg without negatively influencing broiler performance but the further reduction to 165 g/kg compromised FCR. However, the three modifications to the 165 g/kg CP diet failed to enhance broiler performance.

Application of exogenous enzymes: is digestibility an appropriate response variable?

The use of digestible nutrient values for feedstuffs and non-ruminant diets has resulted in significant improvements in ingredient utilisation, pig and poultry performance and efficiency, and reduced feed costs and environmental waste. The use of exogenous enzymes such as carbohydrases, phytases and proteases in non-ruminant diets has also had a profound effect on meat production, feed efficiency and reduced environmental waste through an improvement in nutrient digestibility. However, the use of nutrient digestibility in the absence of animal growth or efficiency, on individual feed ingredients or complete diets, as an estimate of exogenous enzyme efficacy requires careful consideration. Numerous studies have highlighted a range of factors that will influence the estimated digestibility coefficients. These include but are not limited to: differences in methods employed, the use of a point-in-time measure of nutrient digestion versus growth over the lifetime of the chicken or pig, adjustment (or not) for endogenous losses, age of the animal, production status and nutritional status of the diet. These factors can also be influenced by or have an influence on exogenous enzyme efficacy to yield positive, negative, non-significant, or inconclusive effects on nutrient digestion. In addition, exogenous enzyme supplementation of diets has resulted in improvements in nutrient digestibility in the absence of an effect on productivity or efficiency or vice versa. Therefore, the use of nutrient digestibility as a response variable for exogenous enzyme efficacy is informative but only in the presence of growth performance, intake, or meat yield.

Exploring nutritive profile, metabolizable energy, protein, and digestible amino acids contents of indigenous protein sources of different locations for male broilers

2 experiments were conducted to explore nutrient composition, AME, AMEn, standardized ileal digestibility (SID) of CP, and amino acids (AA) of 4 indigenous protein sources including canola meal (CM), rapeseed meal (RSM), guar meal (GM), and sunflower meal (SFM) collected from 2 different locations, Multan (MUL; n = 3) and Sukkur (SKR; n = 3), of Pakistan. Higher (P < 0.05) dry matter (DM), CP, and gross energy (GE), whereas lower (P < 0.05) ash contents were found in SKR, CM, and RSM compared with those from MUL. The MUL GM had higher (P < 0.05) crude fiber (CF) and CP, whereas lower (P < 0.05) GE compared with those from SKR. The SFM from MUL had higher DM, whereas lower CF and CP contents than SKR. In the first experiment, 216 21-d-old male broilers (Ross 308) were distributed over 8 test diets (4 ingredients × 2 locations) and 1 basal diet, with 4 replicates containing 6 birds each (9 × 4 × 6), in a complete randomized design to determine AME and AMEn. The results indicated higher (P < 0.05) AME and AMEn in MUL CM than SKR. In the second experiment, 216 21-d-old male broilers (Ross 308) were raised in 36 cages (6 birds each) to determine SID of CP and AA in a complete randomized design. 8 test diets (4 ingredients × 2 locations) and a protein-free diet, with 4 replicates each, were tested. The SID of CP and some AA were higher (P < 0.05) in MUL CM and RSM than SKR. The SKR GM had a higher (P < 0.05) SID of CP, arginine, methionine, threonine, valine, and cysteine compared with that from MUL. The SFM from MUL had higher (P < 0.05) SID of CP, arginine, histidine, methionine, valine, alanine, aspartate, cysteine, and serine than SKR. In conclusion, major differences do exist between CM, GM, RSM, and SFM from different locations in terms of nutrients, AME, digestible CP, and AA contents for male broilers.

Extending daily feed access intervals does not influence lysine HCl utilization but enhances amino acid digestibilities in broiler chickens

Off-sex, male Ross 308 chickens were offered maize-soy diets without and with 3.5 g/kg lysine monohydrochloride (HCl), which contained 10.0 or 12.8 g/kg digestible lysine, from 7 to 28 D post-hatch. Birds were permitted access to diets at intervals of 12, 16, and 20 h/day. Lysine HCl improved weight gain (1,465 vs. 1,417 g/bird; P < 0.025) and feed conversion ratios (1.351 vs. 1.382; P < 0.005). Extending feed access intervals increased weight gain (1,542 vs. 1,303 g/bird; P < 0.001) and feed intake (2,142 vs. 1,748 g/bird; P < 0.001) but compromised feed conversion ratios (1.390 vs. 1.342; P < 0.001). Extending feed access intervals increased (P < 0.001) both relative crop and gizzard weights and amounts of digesta retained in these organs. Effective lysine HCl utilization in poultry irrespective of feeding frequency, as opposed to pigs, may stem from anticipatory feeding behavior, crop and gizzard functionality, and increased episodes of reverse peristalsis. Collectively, these properties appear to modulate the relative intestinal uptakes of unbound lysine and protein-bound amino acids including lysine. Instructively, extending daily feed access intervals from 12 to 20 h increased average ileal digestibility coefficients of 16 amino acids by 12.8% (0.830 vs. 0.736; P < 0.001), which was linearly related (r = -0.834; P < 0.001) to hourly feed intake rates. Birds given 12 h feed access consumed relatively more feed on an hourly basis and this may have contributed to lesser amino acid digestibilities. As treatment interactions (P > 0.35) between lysine HCl and feed access intervals for parameters of growth performance were not observed, it was concluded that feed access intervals do not influence lysine utilization. The implications of these findings are discussed.

Addition of fermented and unfermented grape skin in broilers' diets: effect on digestion, growth performance, intestinal microbiota and oxidative stability of meat

Grape skin is a source of polyphenols with antioxidant and antimicrobial properties. Little information is available regarding its application in animal feeding. The present study investigated the effect of inclusion of fermented (FS) and unfermented (UFS) grape skin at two different doses (30 g/kg, FS30 and UFS30, and 60 g/kg, FS60 and UFS60) and 200 mg/kg vitamin E (α-tocopheryl acetate) in a corn-soybean diet on growth performance, ileal protein digestibility, ileal and excreta total extractable polyphenols content and digestibility, intestinal microbiota and thigh meat oxidation in broiler chickens. Growth performance was depressed in chickens fed UFS and FS diets. A reduction in ileal protein digestibility was also observed in birds fed UFS, being this effect more pronounced in those fed 60 g/kg. The dietary inclusion of grape skin increased both ileal and excreta polyphenols contents, being higher in birds fed UFS than in those fed FS. Excreta moisture content increased in birds fed UFS and FS diets. No effect of dietary inclusion of grape skin was observed on ileal counts of lactic-acid bacteria and Clostridium, but UFS inclusion in the diet reduced ileal count of Escherichia coli as compared with FS dietary inclusion. After 7 days of refrigerated storage, values of thiobarbituric acid reactive substances (TBARS) were lower in chicken meat when grape skin was added in the diet at 60 g/kg instead of 30 g/kg, and meat from birds fed 60 g/kg of grape skin reached TBARS values similar to those of birds supplemented with vitamin E. In conclusion, high doses of grape skin polyphenols depressed growth performance and protein digestibility, and increased excreta moisture content. Unfermented grape skin contained more polyphenols than FS, and its inclusion in the diet led to higher ileal and excreta polyphenols contents and to a lower ileal count of E. coli. Furthermore, the antioxidant potential of the polyphenols present in grape skin was observed after 7 days of meat storage, with the dose of 60 g/kg of grape skin being as effective as vitamin E supplementation in maintaining oxidative stability of meat.

Effects of reduced crude protein levels, dietary electrolyte balance, and energy density on the performance of broiler chickens offered maize-based diets with evaluations of starch, protein, and amino acid metabolism

The crude protein (CP) content of 4 iso-energetic, maize-based diets containing 11.00 g/kg digestible lysine was reduced in gradations from 200 to 156 g/kg with increasing inclusions of synthetic, or unbound, essential amino acids. A constant dietary electrolyte balance (DEB) of 230 mEq/kg was maintained, but a second 156 g/kg CP diet had a DEB of 120 mEq/kg, and energy densities of the 156 g/kg CP diet were reduced in the sixth and seventh treatments. Each of the 7 dietary treatments were offered to 7 replicate cages (6 birds/cage) or a total of 294 Ross 308 off-sex male broilers from 14 to 35 D posthatch. Reductions in CP from 200 to 156 g/kg did not influence weight gain but quadratically increased feed conversion ratio (FCR) and linearly increased relative abdominal fat-pad weights and feed intakes. The reduction in DEB did not influence growth performance but did adversely influence some amino acid digestibilities. Reducing energy density by 100 kcal/kg did not influence growth performance of birds offered the 156 g/kg CP diet but numerically reduced fat-pad weights. The transition from 200 to 156 g/kg CP diets generally enhanced jejunal and ileal amino acid digestibility coefficients but had diverse effects on free amino acid concentrations in systemic plasma with a remarkable 116% increase in threonine. Starch:protein disappearance rate ratios linearly increased in the jejunum and the ileum following the same transition, and these expanding ratios were related to heavier fat-pads and compromised FCR. This study indicates that reductions in dietary CP from 200 to 172 g/kg supported by inclusions of unbound essential amino acids do not compromise growth performance, but a further reduction to 156 g/kg CP significantly increased FCR. Both heavier relative fat-pad weights and inferior FCR were related to expanding starch:protein disappearance rate ratios, which suggests condensed dietary starch:protein ratios may advantage birds offered reduced CP diets.

Comparative Studies on the Antioxidant Profiles of Curcumin and Bisdemethoxycurcumin in Erythrocytes and Broiler Chickens

Simple Summary

Turmeric, which is the rhizome of Curcuma longa, has a long history for spice and medicine in China, India, and other tropical countries. Curcuminoids, as the principle active compounds of turmeric, consist of curcumin (about 77%), demethoxycurcumin (about 17%), and bisdemethoxycurcumin (about 3%). Studies showed that curcuminoids, especially curcumin, possesses antioxidant, free radical scavenging activities, and thus have a health-promoting effect in human and animals. Of the three curcuminoids, extensive research on the biological activity of curcumin was carried out for decades. However, its natural analogues bisdemethoxycurcumin was relatively less investigated. Based the records, there was still controversy regarding the relative potency of antioxidant activity of curcuminoid that is dependent on different cell types and animal models, which ultimately affected their beneficial effects on the intestinal health and animal production as well. Thus, whether curcumin and bisdemethoxycurcumin shared the same efficiency of antioxidant activity in chicken erythrocytes and broiler chickens remains unknown. Our results demonstrated, for the first time, that the bisdemethoxycurcumin, acting like curcumin, exerted good free radical scavenging activity in erythrocytes and improved the redox status in broilers, although there were some slight differences in their efficiency of antioxidant activities in broiler chickens.

Abstract

The aim of this study was to investigate the antioxidant effects of curcumin and bisdemethoxycurcumin in both 2,20-azobis(2-amidinopropane) dihydrochloride (AAPH)-treated erythrocytes and broiler chickens. In experiment 1, chicken erythrocytes were employed to determine the antioxidant protection against AAPH treatment. Significant differences in hemolysis, superoxide dismutase (SOD) activity, and malondialdehyde (MDA) content were observed between the control and curcuminoids-treated groups. In experiment 2, a total of 480 Arbor Acres broilers with the similar body weights were used. All of the birds were fed basal diet and basal diet with 150 mg/kg curcumin or bisdemethoxycurcumin, respectively. The results showed that curcuminoids significantly increased ADG, serum antioxidant capacity, the glutathione redox potential of small intestine, the gene expression of Nrf2, and its related antioxidant enzymes. Besides, curcumin and bisdemethoxycurcumin increased the antioxidant activities of serum, diet, and excreta while using the 2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt and ferric-reducing antioxidant power methods. It was concluded that bisdemethoxycurcumin, acting like curcumin, exerted good free radical scavenging activity in erythrocytes and improved the redox status in broilers, although there were some slight differences in their efficiency of antioxidant activities.