Kop-Bozbay Canan, Akdag Ahmet, Atan Helin, Ocak Nuh
Department of Animal Science, Faculty of Agriculture, Eskisehir Osmangazi University, 26480, Eskisehir, Turkey.
Department of Animal Science, Faculty of Agriculture, Ondokuz Mayis University, 55139, Samsun, Turkey.
Anim Biosci. 2021 Feb;34(2):295-305. doi: 10.5713/ajas.19.0828. Epub 2020 Feb 25.
The objectives of this study were to compare the effects of normal and low protein content (PC) of starter diet supplemented or not with blends of branched-chain amino acids (BCAAs) on growth performance of broilers under summer conditions and to investigate whether these effects altered some quality traits and the characteristics of gastrointestinal tract.
A total of 768 mixed-sex broiler chicks (Ross 308, one-d-old) with an average initial body weight (BW) of 47.6±1.03 g were allocated into six treatments with four replications in 2×3 factorial arrangement. Factors were: PC, normal (N, 22% to d 15); and low (L, 20% to d 15); and added BCAA blends, L-leucine, L-isoleucine, and L-valine at zero (0L:0I:0V); 1.0, 0.25, and 0.25 (4L:1I:1V); or 1.0, 0.25, 0.75 (4L:1I:3V) g/kg of diet. Hence, six dietary treatments were named as N0L:0I:0V, N4L:1I:1V, N4L:1I:3V, L0L:0I:0V, L4L:1I:1V, and L4L:1I:3V. Average indoor temperature and humidity were 32.8°C±1.7°C and 61.1%±4.12%, respectively.
BW, feed conversion ratio (FCR) and carcass weight were not affected by PC, BCCA and their interaction (p>0.05). The L diets decreased the water holding capacity of the breast (p = 0.002) and thigh (p = 0.050) meats and dressing percentage (p = 0.005) compared to the N diets. The 4L:1I:1V diet decreased breast yield compared to the 0L:0I:0V diets (p = 0.041). The effect of PC on feed intake, mortality and gastrointestinal trait weight were depended on the L:I:V ratios under summer conditions due to interactions between factors (p<0.05). The FI and mortality of L4L:1I:1V broilers were lower than those of N4L:1I:1V birds (p<0.05).
It was concluded that the blends of BCAAs used failed to improve performance and to promote breast yields, because diets with normal or with reduced protein supplemented or not with BCAAs up to d 15 produced a similar BW and FCR in broilers raised in hot-climate conditions.
本研究旨在比较夏季条件下，起始日粮中正常蛋白质含量（PC）和低蛋白质含量且添加或不添加支链氨基酸（BCAAs）混合物对肉鸡生长性能的影响，并研究这些影响是否改变了一些品质性状和胃肠道特征。
将768只1日龄罗斯308混合性别肉鸡雏鸡（平均初始体重[BW]为47.6±1.03克）按照2×3析因设计分为6个处理组，每个处理组有4个重复。因素包括：PC，正常（N，至15日龄为22%）；低（L，至15日龄为20%）；以及添加的BCAA混合物，L-亮氨酸、L-异亮氨酸和L-缬氨酸的添加量分别为零（0L:0I:0V）；1.0、0.25和0.25（4L:1I:1V）；或1.0、0.25、0.75（4L:1I:3V）克/千克日粮。因此，6种日粮处理分别命名为N0L:0I:0V、N4L:1I:1V、N4L:1I:3V、L0L:0I:0V、L4L:1I:1V和L4L:1I:3V。室内平均温度和湿度分别为32.8°C±1.7°C和61.1%±4.12%。
体重、饲料转化率（FCR）和胴体重不受PC、BCCA及其交互作用的影响（p>0.05）。与N日粮相比，L日粮降低了胸肉（p = 0.002）和腿肉（p = 0.050）的持水能力以及屠宰率（p = 0.005）。与0L:0I:0V日粮相比，4L:1I:1V日粮降低了胸肉产量（p = 0.041）。由于因素间的交互作用，夏季条件下PC对采食量、死亡率和胃肠道性状重量的影响取决于L:I:V比例（p<0.05）。L4L:1I:1V组肉鸡的采食量和死亡率低于N4L:1I:1V组肉鸡（p<0.05）。
得出的结论是，所使用的BCAAs混合物未能提高性能和促进胸肉产量，因为在炎热气候条件下饲养的肉鸡中，至15日龄时添加或不添加BCAAs的正常蛋白质或低蛋白质日粮产生了相似的体重和FCR。
