Ceppi A, Blum J W
Division of Nutrition Pathology, University, Berne, Switzerland.
Zentralbl Veterinarmed A. 1994 Aug;41(6):443-58. doi: 10.1111/j.1439-0442.1994.tb00111.x.
Effects of subcutaneous (s.c.) administration of 50 micrograms/kg body weight of recombinant bovine growth hormone (rbGH) or saline were studied for 11 weeks in 40 intact male veal calves supplied 50 mg or 10 mg of iron (Fe)/kg of milk replacer (MR). Feed intake, average daily gain and growth: feed ratio were reduced in Fe-deficient calves, but not significantly influenced by rbGH. Plasma Fe and haemoglobin concentration, red-cell number and packed cell volume were decreased in Fe-deficient calves (P < 0.05) and rbGH further reduced red-cell number in Fe-deficient calves (P < 0.05). The age-dependent increase of total Fe binding capacity was greater in Fe-deficient calves and enhanced by rbGH (P < 0.05). Plasma urea concentrations increased, whereas glucose (G) and triiodothyronine (T3) levels decreased in Fe-deficient calves. rbGH significantly increased G in calves fed MR containing 50 mg/kg (P < 0.05) and influenced urea concentrations (P < 0.05). Plasma insulin (I) and IGF-I concentrations were lower in Fe-deficient calves (P < 0.05). Plasma GH in the first hours after rbGH injections increased (P < 0.05) to higher levels in calves fed 10 than in those fed 50 mg Fe/kg MR, but incremental changes were comparable. In conclusion, low Fe intake caused haematologic, metabolic and endocrine changes. Plasma IGF-I, I and T3 concentrations after rbGH administration and effects of rbGH on IGF-I in Fe-deficient calves were reduced, even though plasma GH levels were increased.
在40头完整的雄性犊牛中，研究了皮下注射50微克/千克体重的重组牛生长激素（rbGH）或生理盐水11周的效果，这些犊牛的代乳料（MR）中添加了50毫克或10毫克铁（Fe）/千克。缺铁犊牛的采食量、平均日增重和生长：饲料比降低，但不受rbGH的显著影响。缺铁犊牛的血浆铁和血红蛋白浓度、红细胞数量和红细胞压积降低（P<0.05），rbGH进一步降低了缺铁犊牛的红细胞数量（P<0.05）。缺铁犊牛中铁结合能力的年龄依赖性增加更大，且rbGH增强了这种增加（P<0.05）。缺铁犊牛的血浆尿素浓度升高，而葡萄糖（G）和三碘甲状腺原氨酸（T3）水平降低。rbGH显著增加了饲喂含50毫克/千克MR的犊牛的G（P<0.05），并影响了尿素浓度（P<0.05）。缺铁犊牛的血浆胰岛素（I）和IGF-I浓度较低（P<0.05）。注射rbGH后的最初几个小时内，饲喂10毫克Fe/千克MR的犊牛血浆GH升高（P<0.05）至更高水平，但增量变化相当。总之，低铁摄入导致血液学、代谢和内分泌变化。尽管血浆GH水平升高，但缺铁犊牛注射rbGH后的血浆IGF-I、I和T3浓度以及rbGH对IGF-I的影响均降低。
