Department of Animal Biosciences, University of Guelph, Guelph N1G2W1, ON, Canada.
Department of Animal Biosciences, University of Guelph, Guelph N1G2W1, ON, Canada.
Poult Sci. 2020 Jun;99(6):3086-3091. doi: 10.1016/j.psj.2020.01.032. Epub 2020 Mar 26.
Emerging market differentiation for broiler meat from strains exhibiting a range of growth rates is necessitating comparative research on various physiological and production aspects of these strains. The objective of the present study was to compare select gastrointestinal, tibial, and plasma attributes in a sample of 48-day-old (50 male and 50 female) broilers obtained from fast-and slow-growing flocks maintained under similar feed and management regimens. Eight birds were randomly selected from a fast (B; representative of modern commercial strains) and each of the 4 slow-growing strains (SG; D, H, M, and E). The strains differed by estimated time to reach 2.2 kg bodyweight corresponding to 36, 50, 42, 44, and 50 D for B, D, H, M, and E, respectively. Blood samples were collected to determine plasma metabolites, and birds were subsequently euthanized, weighed, and necropsied for gizzard and small intestine weight, jejunal tissue for histomorphology, ceca digesta samples for concentration of short-chain fatty acids (SCFA) and left tibia for ash content. Gizzard was heavier (P < 0.01) for D, H, and M than that for B and E, whereas the small intestine was lighter (P < 0.01) for B, D, and H than for M and E. There were no (P > 0.05) strain differences on SCFA, jejunal villus height and crypt depth, plasma proteins, and electrolytes. Strains D, H, and M exhibited higher (P = 0.01) tibia ash concentration than B; E was intermediate and not different (P > 0.05) from any strain. Specifically, the tibia ash for B, D, H, SG 3, and E were 1.24, 1.44, 1.43, 1.49, and 1.39 g/kg BW, respectively. The B birds showed higher (P < 0.01) plasma concentrations of aspartate transaminase, creatine kinase, lactate dehydrogenase, and creatinine than SG strains. In conclusion, although B and some SG strains had lighter gastrointestinal tract indicative of energy efficiency, higher circulating plasma enzymes in B birds suggested impaired hepatic function. Moreover, lower tibia ash in B suggested disproportionate body mass relative to skeletal support.
新兴市场对表现出不同生长速度的肉鸡的需求正在促使人们对这些品种的各种生理和生产方面进行比较研究。本研究的目的是比较快速和慢速生长鸡群中 48 日龄（50 只雄性和 50 只雌性）肉鸡的选择胃肠道、胫骨和血浆属性。从快速（B；代表现代商业品种）和 4 个慢速生长品种（SG；D、H、M 和 E）中各随机选择 8 只鸡。这些品种的估计体重达到 2.2 公斤的时间不同，分别对应 B、D、H、M 和 E 的 36、50、42、44 和 50 天。采集血样以确定血浆代谢物，然后对鸟类进行安乐死、称重和剖检，以测量胃和小肠的重量、空肠组织的组织形态学、盲肠内容物的短链脂肪酸（SCFA）浓度和左侧胫骨的灰分含量。D、H 和 M 的胃重（P<0.01）大于 B 和 E，而 B、D 和 H 的小肠重量（P<0.01）小于 M 和 E。SCFA、空肠绒毛高度和隐窝深度、血浆蛋白和电解质方面没有（P>0.05）品种差异。品种 D、H 和 M 的胫骨灰分浓度高于 B（P=0.01）；E 处于中间位置，与任何品种都没有差异（P>0.05）。具体来说，B、D、H、SG3 和 E 的胫骨灰分分别为 1.24、1.44、1.43、1.49 和 1.39 g/kg BW。B 鸟的天冬氨酸转氨酶、肌酸激酶、乳酸脱氢酶和肌酐的血浆浓度高于 SG 株（P<0.01）。总之，尽管 B 和一些 SG 品种的胃肠道较轻，表明能量效率较高，但 B 鸟的循环血浆酶较高表明肝功能受损。此外，B 的胫骨灰分较低表明相对于骨骼支撑的身体质量不成比例。
