Department of Animal Science, Faculty of Agricultural and Food Sciences, Université Laval, Quebec City G1V 0A6, Quebec, Canada.
Department of Animal Science, Faculty of Agricultural and Food Sciences, Université Laval, Quebec City G1V 0A6, Quebec, Canada.
Poult Sci. 2023 Nov;102(11):103041. doi: 10.1016/j.psj.2023.103041. Epub 2023 Aug 18.
This study investigated the effect of reducing dietary crude protein (CP) content in the grower and finisher diets of broiler chickens on breast meat quality, muscle protein functionality, growth, carcass yield, and meat yield. To achieve this, a total of 1,269 one-day-old male Ross 308 chicks were fed 1 of 3 diets replicated 9 times each in a randomized complete block design with 9 blocks. The diets included a control (20.4% and 19.5% CP in the grower and finisher phase, respectively), a diet with a 1.5% reduction (CP-1.5%) and a diet with a 3.0% reduction (CP-3.0%) in CP content in both the grower and finisher phases. At the end of the experiment, the reduced-CP diets had no impact on body weight, feed intake, or feed conversion ratio. However, reduced-CP diet resulted in reduced (P < 0.001) total nitrogen intake (-7.46 and -11.94% in CP-1.5% and CP-3.0%, respectively). Breast meat quality was assessed (n = 36 birds/group), and the experimental diets were associated with a slightly increased (P = 0.07) ultimate pH (5.75, 5.79, and 5.81 for the control, CP-1.5%, and CP-3.0%, respectively). Breast fillets from the CP-1.5% and CP-3.0% groups had lower yellowness (b*, P < 0.001) and lower cooking loss (CL, P < 0.001) values than the control. Moreover, the solubility, emulsion activity, and stability indices of the sarcoplasmic and myofibrillar fractions of muscle proteins were not influenced by the diets. CP-1.5% and CP-3.0% diets were associated with an increased (P < 0.001) breast yield (18.39, 19.21, and 19.61% for the control, CP-1.5%, and CP-3.0%, respectively) while leg yield remained unchanged. Additionally, breast meat nutritional properties including protein and lipid contents were not impacted by the experimental diets. In conclusion, the CP content in the grower and finisher diets of broiler chickens can be reduced by as much as 3.0% without detrimental effects on performance or on meat quality as long as birds' amino acid requirements are adequately met.
本研究旨在探讨降低肉鸡生长期和育肥期日粮粗蛋白（CP）含量对鸡胸肉品质、肌肉蛋白功能、生长、胴体产率和肉产量的影响。为此，将 1269 只 1 日龄雄性罗斯 308 雏鸡随机分成 9 个区组，每个区组设 3 个重复，每个重复 9 只鸡，采用完全随机区组设计，分别饲喂 3 种日粮：对照组（生长期和育肥期 CP 含量分别为 20.4%和 19.5%）、CP 降低 1.5%组（CP-1.5%）和 CP 降低 3.0%组（CP-3.0%）。试验结束时，与对照组相比，低 CP 日粮组的体重、采食量和饲料转化率均无显著差异（P＞0.05）。但低 CP 日粮组的总氮摄入量显著减少（分别减少了 7.46%和 11.94%，P＜0.001）。每组选取 36 只鸡进行鸡胸肉品质评估，结果表明，试验日粮组的鸡胸肉最终 pH 值（分别为 5.75、5.79 和 5.81）较对照组略有升高（P=0.07）。CP-1.5%和 CP-3.0%组鸡胸肉的黄度（b*值，P＜0.001）和蒸煮损失（CL，P＜0.001）均低于对照组。此外，日粮对肌肉蛋白的肌浆和肌原纤维部分的溶解度、乳化活性和稳定性指数没有影响。CP-1.5%和 CP-3.0%组的鸡胸肉产率（分别为 18.39%、19.21%和 19.61%）均高于对照组，而腿肉产率保持不变。此外，试验日粮对鸡胸肉的营养特性（包括蛋白质和脂肪含量）没有影响。综上所述，只要满足肉鸡的氨基酸需求，肉鸡生长期和育肥期日粮的 CP 含量可降低 3.0%而不影响生产性能和肉品质。
