Effects of starter feeding and early weaning on developmental expressions of IGF-I gene in liver and IGF-IR gene in rumen of lambs from birth to eighty-four days of age

Abstract

The early weaning and starter feeding have significant effects on lamb growth and digestive tract development. However, it is not clear whether the expression of IGF-1/IGF-1R genes could be affected by feeding starter and weaning. Therefore, a total of 102 Hu male neonatal lambs were randomly divided into 3 groups: fed with starter at 42d + weaned at 56d (group A), fed with starter at 7d + weaned at 28d (group B) and fed with starter at 7d + weaned at 56d (group C), to explore the effects of starter feeding and weaning age on developmental expressions of IGF-I gene in liver and IGF-IR gene in rumen of Hu sheep. The results showed that IGF-I and IGF-IR genes were expressed extensively in various tissues of lambs, the expression of IGF-I was significantly higher in liver (p < 0.01), while the expression of IGF-IR was higher in rumen among gastrointestinal tissues. The mRNA level of IGF-I of group C was strikingly higher than that of group A at 28, 70, and 84d (p < 0.01) in liver, respectively. Rumen mRNA level of IGF-IR of group C was prominently higher than that of group A at 70d and 84d (p < 0.05), respectively. However, IGF-IR expression of group A was higher than that of group C at 14 and 42d (p < 0.05). The mRNA level of IGF-I of group B was significantly higher than that of group C at 42, 56, 70, and 84d (p < 0.01) in liver, while IGF-IR expression of group B was higher than that of group C at 70d (p < 0.01). In conclusion, early weaning and starter feeding affected liver IGF-I mRNA and rumen IGF-IR mRNA expression.

Keywords:

• IGF-1
• IGF-1R
• starter
• weaning
• lambs
• liver

Disclosure statement

No potential conflict of interest was reported by the author(s).

Author contributions

C. Li and X. X. Zhang: conceived and designed the study. F. T. Mo, F. D. Li, X. J. Wang, W. M. Wang, Y. F. La, T, Liu. B. S. Li and C. Li: contributed to the biological sample collection and prepared. C. Li, X. X. Zhang, W. M. Wang, T. Liu: performed the experiment. C. Li and X. X. Zhang: wrote the manuscript. C. Li and X. X. Zhang: revised the paper. All authors read and approved the final manuscript.

Additional information

Funding

This work was supported by the National Natural Science Foundation of China [grant no. 31760651], the Earmarked Fund for China Agriculture Research System [grant no. CARS-38], and the National Joint Research on improved breeds of Livestock and Poultry [grant no.19210365].