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| 1 | Progress towards reduced-crude protein diets for broiler chickens and sustainable chicken-meat production显示文摘The prime purpose of this review is to explore the pathways whereby progress towards reduced-crude protein(CP)diets and sustainable chicken-meat production may be best achieved.Reduced-CP broiler diets have the potential to attenuate environmental pollution from nitrogen and ammonia emissions;moreover,they have the capacity to diminish the global chicken-meat industry’s dependence on soybean meal to tangible extents.The variable impacts of reduced-CP broiler diets on apparent amino acid digestibility coefficients are addressed.The more accurate identification of amino acid requirements for broiler chickens offered reduced-CP diets is essential as this would diminish amino acid imbalances and the deamination of surplus amino acids.Deamination of amino acids increases the synthesis and excretion of uric acid for which there is a requirement for glycine,this emphasises the value of so-called“non-essential”amino acids.Starch digestive dynamics and their possible impact of glucose on pancreatic secretions of insulin are discussed,although the functions of insulin in avian species require clarification.Maize is probably a superior feed grain to wheat as the basis of reduced-CP diets;if so,the identification of the underlying reasons for this difference should be instructive.Moderating increases in starch concentrations and condensing dietary starch:protein ratios in reduced-CP diets may prove to be advantageous as expanding ratios appear to be aligned to inferior broiler performance.Threonine is specifically examined because elevated free threonine plasma concentrations in birds offered reduced-CP diets may be indicative of compromised performance.If progress in these directions can be realised,then the prospects of reduced-CP diets contributing to sustainable chicken-meat production are promising. | Sonia Yun Liu Shemil P.Macelline Peter V.Chrystal Peter H.Selle | 2021 | Journal of Animal Science and Biotechnology2021，12，3： | 5 |
| 2 | Protein sources and starch-protein digestive dynamics manipulate growth performance in broiler chickens defined by an equilateraltriangle response surface design显示文摘A total of 360 male,off-sex Ross 308 chicks were offered 10 dietary treatments from 14 to 35 d post ehatch 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. | Shemil P.Macelline Peter V.Chrystal Peter H.Selle Sonia Y.Liu | 2022 | Animal Nutrition2022，，2： | 2 |
| 3 | Implications of excreta uric acid concentrations in broilers offered reduced crude protein diets and dietary glycine requirements for uric acid synthesis显示文摘In a previous experiment,male Ross 308 broiler chickens were offered dietary treatments with 3 levels of crude protein(222,193,165 g/kg)and 3 feed grains(ground maize,ground wheat,whole wheat)from 7 to 35 d post-hatch.Maize-based diets supported superior growth performance in comparison to wheatbased diets.Uric acid concentrations in excreta were retrospectively determined and related to total nitrogen(N)excreta concentrations.Uric acid concentrations ranged from 28.5 to 69.4 mg/g and proportions of uric acid-N to total excreta-N ranged from 27.4%to 42.6%in broiler chickens offered the 3×3 factorial array of dietary treatments.Proportions of uric acid-N to total N in excreta in birds offered the165 g/kg CP,maize-based diet were significantly lower by 10.6 percentage units(27.4%versus 38.0%;P=0.00057)than their wheat-based counterparts.Total excreta analysed had been collected from 35 to37 d post-hatch when feed intakes and excreta outputs were monitored.There were linear relationships between proportions of uric acid-N to total N in excreta in birds offered the three 165 g/kg CP diets with weight gain(r=-0.587;P=0.010),feed intake(r=-0.526;P=0.025)and feed conversion ratios(r=0.635;P=0.005).The possibility that increasing uric acid-N proportions in excreta is indicative of excessive ammonia accumulations compromising growth performance is discussed.The mean proportion of dietary glycine involved in uric acid excretion was 49.2%across all dietary treatments but ranged from 25.0%to 80.9%.Thus,the appropriate amount of dietary glycine is variable and largely dependent on the volume of uric acid synthesised and excreted. | Peter H.Selle David I.Cantor Leon R.McQuade Bernard V.McInerney Juliano Cesar de Paula Dorigam Shemil P.Macelline Peter V.Chrystal Sonia Y.Liu | 2021 | Animal Nutrition2021，，4： | 1 |
| 4 | Graded methionine dietary inclusions influence growth performance and apparent ileal amino acid digestibility coefficients and disappearance rates in broiler chickens显示文摘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 postehatch.The parameters assessed included growth performance,nutrient utilisation(apparent metabolisable energy[AME],AME:GE ratios,N retention,Ncorrected 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 postehatch and in hepatic tissue at 14 and 21 d postehatch.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 postehatch.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. | Shemil P.Macelline Peter V.Chrystal Leon R.McQuade Bernard V.Mclnerney Yangsu Kim Yumin Bao Peter H.Selle Sonia Y.Liu | 2022 | Animal Nutrition2022，，1： | 0 |
| 5 | The influence of dietary crude protein concentrations,grain types and arginine:lysine ratios on the performance of broiler chickens显示文摘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 2×2×2factorial 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%(2154versus 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. | Shemil P.Macelline Peter V.Chrystal Chanon Inanan Mehdi Toghyani Peter H.Selle Sonia Yun Liu | 2023 | Animal Nutrition2023，，3： | 0 |
| 6 | Identifying the shortfalls of crude protein-reduced,wheat-based broiler diets显示文摘The objective of this review is to identify the shortfalls of wheat-based,crude protein(CP)-reduced diets for broiler chickens as wheat is inferior to maize in this context but to inconsistent extents.Inherent factors in wheat may be compromising gut integrity;these include soluble non-starch polysaccharides(NSP),amylase trypsin inhibitors(ATI)and gluten.Soluble NSP in wheat induce increased gut viscosities,which can lead to compromised gut integrity,which is not entirely ameliorated by NSP-degrading feed enzymes.Wheat ATI probably compromise gut integrity and may also have the capacity to increase endogenous amino acid flows and decrease apparent starch and protein digestibilities.Gluten inclusions of 20 g/kg in a maize-soy diet depressed weight gain and feed intake and higher gluten inclusions have been shown to activate inflammatory cytokine-related genes in broiler chickens.Further research is required,perhaps particularly in relation to wheat ATI.The protein content of wheat is typically higher than maize;importantly,this results in higher inclusions of non-bound amino acids in CP-reduced broiler diets.These higher inclusions could trigger post-enteral amino acid imbalances,leading to the deamination of surplus amino acids and the generation of ammonia(NH3)which,if not adequately detoxified,results in compromised growth performance from NH3overload.Thus,alternatives to nonbound amino acids to meet amino acid requirements in birds offered CP-reduced,wheat-based diets merit evaluation.The digestion of wheat starch is more rapid than that of maize starch which may be a disadvantage as the provision of some slowly digestible starch in broiler diets may enhance performance.Alternatively,slowly digestible starch may result in more de novo lipogenesis.Therefore,it may prove instructive to evaluate CP-reduced diets based on maize-wheat and/or sorghum-wheat blends rather than entirely wheat.This would reduce non-bound amino acid inclusions by lowering dietary CP derived from feed grains and may enhance starch digestive dynamics by retarding starch digestion rates.Also,the use of biomarkers to monitor gut integrity in broiler chickens is examined where calprotectin,ovotransferrin and possibly citrulline appear to hold promise,but their validation requires further research. | Peter H.Selle Shemil P.Macelline Shiva Greenhalgh Peter V.Chrystal Sonia Y.Liu | 2022 | Animal Nutrition2022，，4： | 0 |
| 7 | Negative consequences of reduced protein diets supplemented with synthetic amino acids for performance,intestinal barrier function,and caecal microbiota composition of broiler chickens显示文摘The consequences of feeding broiler chickens with reduced protein(RP)diets for gut health and barrier function are not well understood.This study was performed to elucidate the effect of reducing dietary protein and source of protein on gut health and performance parameters.Four experimental diets included 2 control diets with standard protein levels either containing meat and bone meal(CMBM)or an all-vegetable diet(CVEG),a medium RP diet(17.5%in growers and 16.5%in finisher),and a severe RP diet(15.6%in grower and 14.6%in finisher).Off-sex Ross 308 birds were assigned to each of the 4 diets and performance measurements were taken from d 7 to 42 post-hatch.Each diet was replicated 8 times(10 birds per replicate).A challenge study was conducted on additional 96 broilers(24 birds per diet)from d 13 to 21.Half of the birds in each dietary treatment were challenged by dexamethasone(DEX)to induce a leaky gut.Feeding birds with RP diets decreased weight gain(P<0.0001)and increased feed conversion ratio(P<0.0001)from d 7 to 42 compared with control diets.There was no difference be-tween CVEG and CMBM control diets for any parameter.The diet containing 15.6%protein increased(P<0.05)intestinal permeability independent of the DEX challenge.Gene expression of claudin-3 was downregulated(P<0.05)in birds fed 15.6%protein.There was a significant interaction between diet and DEX(P<0.05)and both RP diets(17.5%and 15.6%)downregulated claudin-2 expression in DEX-challenged birds.The overall composition of the caecal microbiota was affected in birds fed 15.6%pro-tein having a significantly lower richness of microbiota in both sham and DEX-injected birds.Proteo-bacteria was the main phylum driving the differences in birds fed 15.6%protein.At the family level,Bifidobacteriaceae,Unclassified Bifidobacteriales,Enterococcaceae,Enterobacteriaceae,and Lachnospir-aceae were the main taxa in birds fed 15.6%protein.Despite supplementation of synthetic amino acids,severe reduction of dietary protein compromised performance and intestinal health parameters in broilers,evidenced by differential mRNA expression of tight junction proteins,higher permeability,and changes in caecal microbiota composition. | Reza Barekatain Peter V.Chrystal Tanya Nowland Amy F.Moss Gordon S.Howarth Thi Thu Hao Van Robert J.Moore | 2023 | Animal Nutrition2023，，2： | 0 |
| 8 | Assessment of limiting dietary amino acids in broiler chickens offered reduced crude protein diets显示文摘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(AMEN)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 t Tyr,glycine equivalence(Glyequi),Pro,and Energy(0.5 MJ/kg reduction in AMEN 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 postehatch in a cage study(Exp.1)to gain digestibility and nutrient utilization data;whereas they were offered from 15 to 35 d post ehatch 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 Glyequi 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 Glyequi may potentially limit breast and thigh development. | Craig W.Maynard Michael T.Kidd Peter V.Chrystal Leon R.McQuade Bernie V.McInerney Peter H.Selle Sonia Y.Liu | 2022 | Animal Nutrition2022，，3： | 0 |
| 9 | The influence of non-bound amino acid inclusions and starch-protein digestive dynamics on growth performance of broiler chickens offered wheat-based diets with two crude protein concentrations显示文摘The primary objective of this study was to investigate the influence of high and low inclusions of nonbound amino acid(NBAA)in standard and reduced-crude protein(CP),wheat-based diets on growth performance in broiler chickens.Dietary treatments were formulated to either 210 or 180 g/kg CP.The210 g/kg CP diets contained either 12.1 or 21.1 g/kg NBAA and 180 g/kg CP diets contained either 44.0 or55.5 g/kg NBAA.The formulations also generated different dietary starch:protein ratios which impacted on starch-protein digestive dynamics.Each of the four dietary treatments were offered to 7 replicates of15 birds housed in floor pens from 14 to 35 days post-hatch or a total of 420 male Ross 308 chickens.Growth performance,relative abdominal fat-pad weights,breast muscle and leg shank yields were determined.Ileal starch and protein(N)digestibility coefficients,disappearance rates and starch:protein disappearance rate ratios were defined.Apparent ileal digestibility coefficients and disappearance rates of 16 amino acids were determined at 35 days post-hatch and free concentrations of 20 amino acids in systemic plasma were determined at 34 days post-hatch.The transition from 210 to 180 g/kg CP diets depressed weight gain by 11.3%(1742 versus 1964 g/bird)and FCR by 10.4%(1.606 versus 1.455),although both parameters were subject to treatment interactions.The treatment interaction(P<0.001)observed for FCR was because high NBAA inclusions significantly improved FCR by 4.17%(1.424 versus1.486)in birds offered 210 g/kg CP diets,but significantly depressed FCR by 3.36%(1.632 versus 1.579)in180 g/kg CP diets.A quadratic relationship(r=0.860;P<0.001)between dietary NBAA inclusions and FCR was detected,which indicated that when NBAA inclusions exceed 18.5 g/kg efficiency of feed conversion deteriorated.However,a multiple linear regression(r=0.913;P<0.001)was detected for FCR where both NBAA inclusions and analysed dietary starch:protein ratios were significantly(P<0.001)related to FCR.This relationship indicates that growth performance of broiler chickens offered wheatbased diets is strongly influenced by dietary NBAA inclusions coupled with dietary starch:protein ratios and consideration is given to the possible underlying mechanisms. | Shemil P.Macelline Michael T.Kidd Peter V.Chrystal Mehdi Toghyani Peter H.Selle Sonia Y.Liu | 2023 | Animal Nutrition2023，，4： | 0 |
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