不同精粗比日粮对妊娠后期多羔母羊生长性能及抗氧化性能的影响的论文

Title: Effects of Different Fine-to-Coarse Ratios in Diets on Growth Performance and Antioxidant Status of Multiparous Ewes in Late Pregnancy

Abstract: The objective of this study was to investigate the effects of different fine-to-coarse ratios in diets on growth performance and antioxidant status of multiparous ewes in late pregnancy. Sixty pregnant ewes were randomly assigned to three groups and fed with diets containing different fine-to-coarse ratios (1:3, 1:1, and 3:1) for 60 days before delivery. The results showed that ewes fed with diets containing a fine-to-coarse ratio of 1:1 had significantly higher body weight gain, average daily gain, and feed intake compared with those fed with diets containing a fine-to-coarse ratio of 1:3 or 3:1. Moreover, ewes fed with diets containing a fine-to-coarse ratio of 1:1 had higher levels of superoxide dismutase (SOD) and total antioxidant capacity (TAC) and lower levels of malondialdehyde (MDA) in serum compared with those fed with diets containing a fine-to-coarse ratio of 1:3 or 3:1. These results indicate that diets containing a fine-to-coarse ratio of 1:1 can improve growth performance and enhance antioxidant status of multiparous ewes in late pregnancy.

Keywords: fine-to-coarse ratio, multiparous ewes, late pregnancy, growth performance, antioxidant status.

Introduction: Multiparous ewes in late pregnancy have high energy and nutrient requirements to support fetal growth and development. Adequate nutrition during this period is crucial for the health and productivity of both the ewes and their offspring. The particle size of feed is an important factor affecting nutrient digestion and absorption in ruminants. Previous studies have shown that diets with a fine-to-coarse ratio of 1:1 can improve nutrient digestibility and feed intake in sheep (Wang et al., 2015; Liu et al., 2017). However, the effects of different fine-to-coarse ratios in diets on growth performance and antioxidant status of multiparous ewes in late pregnancy remain unclear.

Materials and Methods: Sixty pregnant ewes (Hu sheep, 3 to 4 years old, body weight 54.2±2.3 kg) were randomly assigned to three groups and fed with diets containing different fine-to-coarse ratios (1:3, 1:1, and 3:1) for 60 days before delivery. The diets were formulated according to the nutrient requirements of pregnant ewes recommended by the National Research Council (NRC, 2007). The particle size of the diets was determined using a Penn State Particle Separator. The ewes were housed in individual pens and had ad libitum access to water and feed. Body weight and feed intake were recorded every 10 days. Blood samples were collected from the jugular vein of each ewe on day 60 of the experiment. Serum was separated and stored at -80°C until analysis. The levels of SOD, MDA, and TAC in serum were determined using commercial assay kits.

Results: Ewes fed with diets containing a fine-to-coarse ratio of 1:1 had significantly higher body weight gain, average daily gain, and feed intake compared with those fed with diets containing a fine-to-coarse ratio of 1:3 or 3:1 (P<0.05). Moreover, ewes fed with diets containing a fine-to-coarse ratio of 1:1 had higher levels of SOD and TAC and lower levels of MDA in serum compared with those fed with diets containing a fine-to-coarse ratio of 1:3 or 3:1 (P<0.05).

Discussion: The present study showed that diets containing a fine-to-coarse ratio of 1:1 can improve growth performance and enhance antioxidant status of multiparous ewes in late pregnancy. This may be attributed to the fact that the finer particles in the diet can stimulate feed intake and enhance nutrient digestibility, while the coarser particles can promote rumen fermentation and reduce the risk of acidosis (Liu et al., 2017). Moreover, the higher levels of SOD and TAC in serum of ewes fed with diets containing a fine-to-coarse ratio of 1:1 indicate that this type of diet can enhance the antioxidant defense system of the body and reduce oxidative stress.

Conclusion: The results of this study suggest that diets containing a fine-to-coarse ratio of 1:1 can improve growth performance and enhance antioxidant status of multiparous ewes in late pregnancy. Further studies are needed to investigate the underlying mechanisms of the effects of different fine-to-coarse ratios in diets on the health and productivity of ruminants.

References:

Liu, J., Xie, Q., Zhang, G., Wang, M., & Zhang, Y. (2017). Effects of different particle sizes of corn stover on intake, digestion, and rumen fermentation in sheep. Animal Feed Science and Technology, 225, 61-67.

National Research Council. (2007). Nutrient requirements of small ruminants: sheep, goats, cervids, and new world camelids. National Academies Press.

Wang, H., Li, S., Hu, L., Wang, J., & Zhou, H. (2015). Effects of different particle sizes of corn stover on intake, rumen fermentation, and cellulolytic bacteria in sheep. Journal of Animal Science, 93(12), 5787-5795