Laboratory of Livestock Physiology, Immunology and Genetics, Department of Biosystems, Faculty of Bioscience Engineering, Katholieke UniversiteitLeuven, Leuven, Belgium.
J Anim Physiol Anim Nutr (Berl). 2009 Aug;93(4):512-9. doi: 10.1111/j.1439-0396.2008.00833.x.
Dietary addition of the leucine metabolite β-hydroxy-β-methylbutyrate (HMB) promotes growth in various species. In addition, HMB is described to enhance immune responses which might be associated with metabolic costs. We elaborated further on the role of HMB in growth, metabolism and immunity of meat-type chickens using the following parameters: zootechnical performance, blood chemistry and a specific immune responses after immunization with a human serum albumin (HSA)/Freund’s (in) complete adjuvant combination. The chickens received commercial feeds either unsupplemented or supplemented with 300 mg HMB/kg feed. β-hydroxy-β-methylbutyrate-supplemented chickens were significantly heavier at 2 weeks of age but this difference was attenuated at later ages. Compared with their unsupplemented controls, cumulative feed conversion was significantly lower in HMB-supplemented chickens. There were no differences in blood chemistry between both dietary treatments. After immunization, HMB significantly attenuated the acute phase protein response at day 1 of post-immunization compared with that of their unsupplemented counterparts. After day 7 post-immunization, body weight gain of the immuno-challenged HMB-supplemented chickens was significantly depressed, but their specific anti-HSA IgG response was significantly enhanced compared with that of their immuno-challenged unsupplemented counterparts. The underlying mechanisms and signalling pathways for these phenomena need to be elucidated. Nevertheless, we are able to conclude that HMB is beneficial for performance under normal circumstances. On the other hand, HMB stimulates the immune response after an immunological challenge, though at the cost of reduced growth.
饲粮添加亮氨酸代谢产物 β-羟基-β-甲基丁酸（HMB）可促进多种物种的生长。此外，HMB 被描述为增强免疫反应，这可能与代谢成本有关。我们使用以下参数进一步阐述了 HMB 在肉用型鸡的生长、代谢和免疫中的作用：生产性能、血液化学和用人血清白蛋白（HSA）/福氏（完全）佐剂组合免疫后的特定免疫反应。鸡只接受商业饲料，要么不添加，要么添加 300mg HMB/kg 饲料。2 周龄时，添加 HMB 的鸡体重明显更重，但这种差异在后期会减弱。与未添加的对照组相比，添加 HMB 的鸡的累计饲料转化率明显更低。两种日粮处理之间的血液化学无差异。与未添加的对照组相比，免疫后，HMB 可显著降低急性蛋白反应在免疫后第 1 天的水平。免疫后第 7 天，免疫挑战的 HMB 添加鸡的体重增加明显受到抑制，但它们的特异性抗 HSA IgG 反应明显高于未添加的免疫对照组。这些现象的潜在机制和信号通路需要阐明。尽管如此，我们可以得出结论，HMB 在正常情况下对性能有益。另一方面，HMB 刺激免疫反应后免疫挑战，尽管以生长减少为代价。
