The influence of dietary crude protein concentrations, grain types and arginine:lysine ratios on the performance of broiler chickens (original) (raw)
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Animal Nutrition , 2023
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. The 210 g/kg CP diets contained either 12.1 or 21.1 g/kg NBAA and 180 g/kg CP diets contained either 44.0 or 55.5 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 of 15 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 versus 1.486) in birds offered 210 g/kg CP diets, but significantly depressed FCR by 3.36% (1.632 versus 1.579) in 180 g/kg CP diets. A quadratic relationship (r ¼ 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 ¼ 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.
Animal Feed Science and Technology, 2002
The apparent ileal digestibility coefficients of amino acids in 107 samples representing 22 food ingredients were determined using 6-week-old broiler chickens. The ingredients assayed included five cereals (barley, maize, sorghum, triticale and wheat), two cereal by-products (rice polishings and wheat middlings), four oilseed meals (canola, cottonseed, soyabean and sunflower meals), full-fat canola, maize gluten meal, four grain legumes (chickpeas, faba beans, field peas and lupins) and five animal protein sources (blood, feather, fish, meat and meat and bone meals). The mean ileal digestibility coefficients of amino acids in wheat and maize were higher than those in sorghum, triticale and barley. However, variations observed in individual amino acid digestibilities among samples within cereal type were greater than those determined between cereals. Threonine and lysine were the least digestible indispensable amino acids in the five cereals evaluated. The most digestible indispensable amino acid was phenylalanine in wheat and, leucine in maize and sorghum. In the case of the wheat middlings and rice polishings, threonine was the least digestible indispensable amino acid and arginine was the best digested. In the oilseed meals assayed, amino acid digestibility was highest for soyabean and sunflower meals, intermediate for canola meal and lowest for cottonseed meal. Ileal digestibility coefficients of amino acids in lupins were found to be slightly lower than those in soyabean meal. The amino acid digestibilities of field peas, faba beans and chickpeas were considerably lower than those of lupins. Digestibility of arginine was the highest and that of threonine was the lowest of the indispensable amino acids in oilseed meals and grain legumes, except in cottonseed meal. Lysine was the least digestible amino acid in cottonseed meal. In the animal protein sources assayed, digestibility coefficients of amino acids in blood meal were high, intermediate in fish meal, and low in meat meal, meat and bone meal and feather meal. Variation in amino acid digestibility coefficients determined for blood meal samples was small. However, wide variations in amino acid digestibilities were observed for other animal protein sources, highlighting significant batch-to-batch differences. In particular, marked variations were determined for meat meal and meat and bone meal samples. Cystine was the least digested amino acid in animal protein meals, with the exception of blood meal in which isoleucine had the lowest digestibility. The limitations of using apparent digestibility values in diet formulations and the concept of the standardized digestibility system to overcome these limitations are discussed.
Poultry Science, 2020
The aim of present study was to determine the influence of the feed form (FF) on standardized ileal digestibility (SID) of nitrogen (N) and amino acids (AA) in 3 protein sources (PS) for broiler chickens. Six diets were tested in a 3 ! 2 factorial arrangement of treatments involving 3 PS (meat and bone meal [MBM], soybean meal [SBM], and canola meal [CM]) in mash and pelleted forms. The basal endogenous N and AA losses were determined by offering a N-free diet in the mash form. From day 1 to 18, the birds were offered a broiler starter diet. The diets and the N-free diet were randomly assigned to 6 replicate cages (8 birds per cage) and fed from day 19 to 23. The ileal digesta were collected on day 23. The SID of N was higher (P , 0.05) in SBM followed by MBM and CM. The average SID of AA in SBM and MBM were similar (P. 0.05), and greater (P , 0.05) than that in CM. The FF had no influence (P. 0.05) on the SID of indispensable AA, the only exception being His, which was reduced (P , 0.05) by pelleting. Pelleting, however, resulted in reduction (P , 0.001) in the SID of all dispensable AA and average of AA. The AA most affected by pelleting was Cys, with a 15.4% decrease in the SID. The standardized ileal digestible contents of protein and the average of indispensable AA and dispensable AA were higher in MBM than in SBM, with CM being the lowest. Pelleting decreased (P , 0.05) the digestible protein and total digestible AA contents. These findings reveal that the FF has a substantial impact on AA digestibility estimates of feed ingredients and it must be considered in AA digestibility assays of ingredients with high protein and AA contents.
Poultry Science , 2023
This study was designed to investigate the impacts of 2 energy densities (13.0 and 12.5 MJ/kg ME) in wheat-based diets with 3 tiers of CP concentrations (210, 190, and 170 g/kg) on the performance of broiler chickens. The parameters assessed included growth performance (15−36 d posthatch), carcass traits, nutrient utilization, starch−protein digestive dynamics, apparent ileal amino acid digestibility coefficients, and the free amino acid and ammonia (NH 3) concentrations in systemic plasma. Also, the feasibility of substituting soybean meal with canola meal in 190 g/kg CP diets was investigated. The dietary CP reduction from 210 to 170 g/kg significantly compromised weight gain by 12.4% (1,890 vs. 2158 g/bird) and FCR by 5.33% (1.501 vs. 1.425). The 0.5 MJ energy density reduction compromised FCR by 3.25% (1.525 vs. 1.477; P = 0.013) in birds offered 170 g/kg CP diets. Reducing
Animals, 2020
The aim was to test additivity of apparent ileal digestibility (AID) and standardized ileal digestibility (SID) of amino acids (AAs) in mixed diets for Ross 308 broiler chickens. Two hundred and eighty-eight, 20-d-old male broiler chickens were assigned to one of six diets, with six birds per cage using a randomized complete block design. The diets consisted of a nitrogen-free diet, three diets containing corn, soybean meal (SBM), and corn distillers dried grains with solubles (CDDGS) as the sole source of nitrogen, respectively, and two mixed diets containing corn, SBM or CDDGS. Chromic oxide was added to the diets as an indigestible index. On day 24, birds were euthanized for ileal digesta collection. Relative proportion of the basal endogenous loss of AAs to total ileal outflow of AAs in corn was greater (p < 0.05) than that of SBM and CDDGS. For the corn-SBM and corn-SBM-CDDGS mixed diets, the AID of AAs differed (p < 0.05) from the predicted values. No difference was obse...
Identifying the shortfalls of crude protein-reduced, wheat-based broiler diets
Animal Nutrition, 2022
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 (NH 3) which, if not adequately detoxified, results in compromised growth performance from NH 3 overload. 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 sorghumewheat 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.
Dietary protein and amino acids-consideration of the undigestible fraction
Poultry science, 2014
A case is made for the application of true ileal amino acid digestibility and true ileal reactive lysine digestibility (lysine availability) in poultry nutrition. Technical aspects of the true ileal digestibility assays are reviewed, as are factors influencing amino acid digestibility in the broiler. There is considerable variation in amino acid digestibility and lysine availability both within and among diverse feedstuffs. Differences in mean amino acid digestibility among feedstuffs, and the variability in the digestibility of an amino acid within a feedstuff should both be taken into account during least-cost dietary formulation.
PLOS ONE, 2022
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 we...
The challenge to reduce crude protein contents of wheat-based broiler diets
Animal Production Science , 2023
The challenge to reduce crude protein (CP) contents of wheat-based broiler diets is both justified and formidable because the performance of broiler chickens offered reduced-CP, wheat-based diets is usually compromised. Moreover, broiler chickens offered wheat-based diets do not accommodate CP reductions as well as do those offered maize-based diets; this appears to stem from the higher protein concentrations and more rapid starch digestion rates of wheat. The higher protein concentrations of wheat than maize result in elevated inclusion levels of non-bound (synthetic, crystalline) amino acids (NBAA). This may be an impediment, because non-bound and proteinbound amino acids are not bioequivalent and intestinal uptakes of NBAA are more rapid than their protein-bound counterparts. This leads to post-enteral amino acid imbalances and the deamination of surplus amino acids, which generates ammonia (NH 3). Because NH 3 is inherently detrimental, it must be detoxified and eliminated as uric acid, which attracts metabolic costs. Moreover, inadequate NH 3 detoxification may seriously compromise broiler growth performance. Also, consideration is given to some intrinsic wheat factors, including soluble non-starch polysaccharides, amylase-trypsin inhibitors and gluten, that may hold relevance. Several strategies are proposed that may enhance the performance of birds offered reduced-CP, wheatbased diets, including capping dietary starch:protein ratios, blending wheat with sorghum, wholegrain feeding in association with phytase, dietary inclusions of L-carnitine and the use of protected or slow-release amino acids. In future research, it should prove instructive to compare different wheats with a wide range of protein contents that, importantly, have been fully characterised for relevant parameters, to ascertain the most appropriate properties. The successful development and adoption of reduced-CP, wheat-based diets would be an enormous advantage for the Australian chicken-meat industry as it would diminish the huge dependence on imported, expensive soybean meal.
Asian-Australasian Journal of Animal Sciences, 2016
The aim of present experiment was to investigate the effect of protein reduction in commercial broiler chicken rations with incorporation of de-oiled rice bran (DORB) and supplementation of limiting amino acids (valine, isoleucine, and/or tryptophan) with ration formulation either on total amino acid (TAA) or standardized ileal digestible amino acids (SIDAA). The experimental design consisted of T 1 , TAA control; T 2 and T 3 , 0.75% and 1.5% protein reduction by 3% and 6% DORB incorporation, respectively by replacing soybean meal with supplemental limiting amino acids to meet TAA requirement; T 4 , SIDAA control, T 5 and T 6 , 0.75% and 1.5% protein reduction by DORB incorporation (3% and 6%) with supplemental limiting amino acids on SIDAA basis. A total of 360 dold fast growing broiler chicks (Vencobb-400) were divided into 36 homogenous groups of ten chicks each, and six dietary treatments described were allocated randomly with six replications. During 42 days trial, the feed intake was significantly (p<0.05) reduced by TAA factor compared to SIDAA factor and protein factor significantly (p<0.05) reduced the feed intake at 1.5% reduction compared to normal protein group. This was observed only during pre-starter phase but not thereafter. The cumulative body weight gain (BWG) was significantly (p<0.05) reduced in TAA formulations with protein step-down of 1.5% (T 3 , 1,993 g) compared to control (T 1 , 2,067 g), while under SIDAA formulations, BWG was not affected with protein reduction of 1.5% (T 6 , 2,076 g) compared to T 4 (2,129 g). The feed conversion ratio (FCR) was significantly (p<0.05) reduced in both TAA and SIDAA formulations with 1.5% protein step-down (T 3 , 1.741; T 6 , 1.704) compared to respective controls (T 1 , 1.696; T 4 , 1.663). The SIDAA formulation revealed significantly (p<0.05) higher BWG (2,095 g) and better FCR (1.684) compared to TAA formulation (2,028 g; 1.721). Intake of crude protein and all limiting amino acids (SID basis) was higher in SIDAA group than TAA group with resultant higher nitrogen retention (4.438 vs 4.027 g/bird/d). The nitrogen excretion was minimized with 1.5% protein reduction (1.608 g/bird) compared to normal protein group (1.794 g/bird). The serum uric acid concentration was significantly reduced in T 3 (9.45 mg/dL) as compared to T 4 (10.75 mg/dL). All carcass parameters were significantly (p<0.05) higher in SIDAA formulation over TAA formulation and 1.5% protein reduction significantly reduced carcass, breast and thigh yields. In conclusion, the dietary protein can be reduced by 0.75% with TAA formulation and 1.5% with SIDAA formulation through DORB incorporation and supplementation of limiting amino acids and among formulations, SIDAA formulation was better than TAA formulation.