Study On The Effect Of Astaxanthin Supplementation In Sow Diets For Live Births And Piglet Daily Weight Gain During Late Gestation And Lactation

During pregnancy and lactation,sows experience severe oxidative stress due to the increase in their own energy demand and metabolic rate,which can affect placental function and normal fetal development,leading to a decrease in the number of live-born piglets.In addition,newborn piglets,due to their underdeveloped antioxidant system,also suffer from severe postnatal oxidative stress,resulting in a decrease in their daily weight gain.Astaxanthin(Asta)is a small molecule substance with a wide range of biological activities and is one of the most potent antioxidants known to date.In the aquaculture industry,it is a reproductive and growth regulator for aquatic animals.However,the effects of Asta on the number of live-born piglets and piglet daily weight gain are currently unclear.Therefore,this study aims to supplement Asta in sow feed to explore its effects on the number of live-born piglets and piglet daily weight gain.In this study,a total of 80 large white sows in their second litter were randomly and equally divided into 4 groups and then assigned to dietary treatments supplemented with 0,4,8 and 12 mg/kg Asta,fed from 85 days of gestation to the end of 21 days of lactation.This study evaluated: the effect of Asta on sow reproductive performance,including litter size,live births,stillbirths,weak litters(birth weight <1.0 kg),weaning litters and placental weight;the effect of Asta on piglet growth performance,including litter weight and average daily gain on days 0,7,14 and 21;the content of Asta in placental tissue,sow colostrum and piglet liver tissue;the effect of Asta on the redox status of placental tissue and histomorphology,the former including reactive oxygen species(ROS),antioxidant-related proteins including catalase(CAT),superoxide dismutase 1(SOD1)and superoxide dismutase 2(SOD2);the effect of Asta on the redox status of colostrum,sow serum and piglet serum,including ROS,malondialdehyde(MDA),total antioxidant capacity(T-AOC),superoxide dismutase(SOD)levels and the effect of Asta on piglet small intestine development and sow gut microbes.The following main results were obtained in this study:1.dietary supplementation of 4～12 mg/kg Asta in late gestation and lactating sows did not affect the total litter size of sows,but significantly improved(P < 0.05)the live litter size of sows(control vs Asta treatment: 10.4 ± 0.62 vs 11.2 ± 0.29,11.7 ± 0.26,11.2 ± 0.33)and significantly improved(P < 0.05)the litter mean daily weight gain(control vs Asta treatment: 1.60 ± 0.78 kg vs 1.96 ± 0.10 kg,2.00 ± 0.82 kg,1.98 ± 0.10 kg),and no significant difference between Asta treatment groups.2.Asta content in the sow placenta,colostrum,and piglet liver increased significantly(P < 0.05)with increasing concentrations of Asta in the diet of late pregnant and lactating sows,indicating that Asta in the diet of late pregnant sows can be transferred to the fetus through the placenta,and Asta in the diet of lactating sows can be transferred to the piglets through the milk.3.Supplementation of 8 and 12 mg/kg Asta in the diet of late pregnant sows significantly reduced(P < 0.05)oxidative stress levels in the placenta and significantly increased(P < 0.05)capillary formation in the placental villous membrane.4.Supplementation of 4～12 mg/kg Asta in the diet of lactating sows significantly reduced oxidative stress levels in piglet serum(P < 0.05)and significantly increased(P <0.05)villus height and the villus height/crypt depth ratio in the piglet duodenum,but significantly decreased(P < 0.05)duodenal crypt depth.5.Dietary supplementation of 4～12 mg/kg Asta in sows during late gestation and lactation significantly reduced(P < 0.05)the oxidative stress to which they were subjected.In addition,Asta significantly increased(P < 0.05)the relative abundance of genus Eubacterium＿coprostanoligenes＿group and NK4A214＿group in the gut of sows in late gestation,which was negatively correlated with serum ROS and MDA levels in sows in late gestation;Asta significantly decreased(P < 0.05)the relative abundance of genus Eubacterium＿coprostanoligenes＿group in the sow intestine at parturition,which was significantly negatively correlated with placental weight and piglet birth weight(P < 0.05);in late lactation,Asta significantly decreased(P < 0.05)the relative abundance of genus p-251-o5,Porphyromonas and Bacteroides,which were positively correlated with serum ROS and MDA levels,but negatively correlated with T-AOC and SOD,the number of weaned piglets and weaning litter weight.In conclusion,oxidative stress impairs sow reproduction and piglet growth performance.Supplementing 4～12 mg/kg Asta in sow diets can effectively transfer to the fetus through the placenta,alleviate oxidative stress,increase placental blood vessel formation,and thus increase the number of live-born piglets.Asta can also reshape the sow gut microbiota structure,which is associated with reducing oxidative stress in sows and improving their reproductive performance indicators.Furthermore,Asta can be transferred to piglets through sow milk,reducing oxidative stress,promoting intestinal development,and ultimately enhancing their average daily weight gain.In addition,8 mg/kg Asta can serve as the most appropriate concentration to increase the number of live-born piglets and improve piglet average daily weight gain.