Department of Animal Science, Federal University of Lavras, 37200-900 Lavras, Minas Gerais, Brazil.
Department of Biology and Animal Science, São Paulo State University, 15385-000, Ilha Solteira, São Paulo, Brazil.
Animal. 2021 Feb;15(2):100120. doi: 10.1016/j.animal.2020.100120. Epub 2020 Dec 15.
The excessive accumulation of abdominal fat in broilers is an economic waste. Supplemental dietary L-arginine has been shown to reduce lipogenesis in broilers, but studies on this subject are still scarce. Two experiments were conducted in a 5×2 factorial design, with five L-arginine concentrations in diets (0, 3, 6, 9 and 12 g/kg) provided to male and female broilers, from 29 to 42 days of age, reared in boxes or cages, with six replicates of 23 broilers per box and six replicates of three broilers per cage, totalling 1560 broilers. Data on performance, carcass and cuts yield, abdominal fat deposition, chemical composition of the breast, lipid profile and liver enzyme activity were evaluated in experiment 1. In experiment 2, the balance and retention of nitrogen, metabolizability coefficients and metabolizable energy of feed were determined and the treatments were evaluated in six replicates of three broilers per cage, totalling 180 broilers. In both experiments, there was no interaction (P > 0.05) between L-arginine concentration in the diet and sex of the broilers for all parameters evaluated. Male broilers showed higher (P < 0.05) weight gain, noble cuts yield, levels of CP and mineral matter in the breast, better feed conversion (P < 0.05) and lower (P < 0.05) malic enzyme activity in the liver and abdominal fat deposition. On the other hand, regardless of sex, the increase in L-arginine concentration in the diet improved (P < 0.05) the feed conversion in addition to reducing (P < 0.05) serum levels of total cholesterol and low-density lipoprotein cholesterol, the malic enzyme activity in the liver and abdominal fat deposition. In conclusion, male broilers had better productive results than females. However, supplementing the diet of male or female broilers from 29 to 42 days of age with L-arginine at a concentration of 6.87 g/kg represents a nutritional strategy to improve feed conversion and reduce circulating triacylglycerol and cholesterol levels, NADPH synthesis by liver malic enzyme and abdominal fat deposition, without negatively affecting the carcass and noble cuts yield, the amount of nitrogen excreted by the broilers and the energy value of the feed.
肉鸡腹脂过度积累是一种经济浪费。补充膳食 L-精氨酸已被证明可以减少肉鸡的脂肪生成，但关于这个主题的研究仍然很少。本研究采用 5×2 析因设计，在 29 至 42 日龄的雄性和雌性肉鸡的日粮中分别添加 0、3、6、9 和 12 g/kg L-精氨酸，在箱或笼中饲养，每个处理设 6 个重复，每个重复 23 只鸡，笼养设 6 个重复，每个重复 3 只鸡，共 1560 只肉鸡。试验 1 评估了生产性能、屠体和切块产量、腹部脂肪沉积、胸肌化学成分、脂质谱和肝酶活性。在试验 2 中，测定了氮平衡和保留、饲料代谢系数和代谢能，并在笼养的 6 个重复（每个重复 3 只鸡）中评估了处理，共 180 只鸡。在这两个试验中，日粮中 L-精氨酸浓度与肉鸡性别之间没有互作（P > 0.05）。雄性肉鸡表现出更高的体重增重（P < 0.05）、优质切块产量、胸肌 CP 和矿物质水平、更好的饲料转化率（P < 0.05）和更低的（P < 0.05）肝苹果酸酶活性和腹部脂肪沉积。另一方面，无论性别如何，日粮中 L-精氨酸浓度的增加都可以改善（P < 0.05）饲料转化率，此外还可以降低（P < 0.05）血清总胆固醇和低密度脂蛋白胆固醇水平、肝苹果酸酶活性和腹部脂肪沉积。总之，雄性肉鸡比雌性肉鸡具有更好的生产性能。然而，在 29 至 42 日龄期间，雄性或雌性肉鸡的日粮中添加 6.87 g/kg 的 L-精氨酸是一种营养策略，可以改善饲料转化率，降低循环三酰甘油和胆固醇水平、NADPH 通过肝苹果酸酶的合成和腹部脂肪沉积，而不会对屠体和优质切块产量、肉鸡排泄的氮量和饲料的能量值产生负面影响。
