| This paper aims to study the effects of low-protein and low-phosphorus diets on growth and reproductive performance,serum biochemical indicators,nitrogen emissions,fecal microorganisms of lactating sows,and growth performance of suckling piglets as well as maternal production economic benefits,so as to provide scientific data for the application of low protein and low phosphorus diet.Experiment 1: 38 Landrance×Large White healthy sows with similar breed,parity,expected date of delivery,last litter performance,weight and estrangement were selected and randomly divided into 2 groups,each with 19 replicates with 1 sow each replicate.The control group was fed a basic diet(CP = 17%),and the test group was fed a low-protein diet(CP = 16%).The trial lasted 21 days.The results were shown as follows:(1)Low protein diets had no significant effects on average feed intake per sow,average daily intake and backfat thickness loss,weaning-estrous interval of lactating sows,estrus rate at 7 days after weaning,estrus mating rate,and return rate for the next litter in lactating sows(P>0.05);Low protein diet significantly increased the total lactation of lactating sows(P<0.05),significantly reduced the feed-to-milk ratio(P<0.05),and did not affected the milk quality of lactating sows(P>0.05);(2)Low protein diets significantly increase serum albumin levels in lactating sows(P<0.05);significantly reduced the content of free fatty acids in serum(P=0.0001)No significant effect on the content of alkaline phosphatase and IGF-1(P>0.05);(3)Low protein diet significantly increased the litters of piglets at weaning,weaning litter weight gain,average daily weight gain,and piglet survival(P<0.05),and significantly reduced the diarrhea rate of suckling piglets(P<0.05);(4)Low protein diets significantly reduced the abundance of two types of pathogens(Veillonellaceae,and Dialister),in the faeces of lactating sows;(5)Low protein diets significantly increased the average nitrogen intake of lactating sows(P<0.05),and significantly reduced the fecal nitrogen,urine nitrogen emissions,and total nitrogen emissions of lactating sows(P<0.05);(6)Feeding low protein diets reduced the feed cost per sow by 27.54 RMB,and reduced the production cost per piglet by 3.34 RMB.Experiment 2: 40 Landrance ×Large White healthy sows with similar breeds,parity,predicted date of delivery,last litter performance,weight,and estrus were selected and randomly divided into 2 groups,each with 20 replicates,with 1 sow each replicate.The control group was fed basic diets(CP = 17%,P = 0.62%),and the experimental group was fed low-protein and low-phosphorus diets(CP = 16%,P =0.55%).The trial lasted 21 days.The results were shown as follows:(1)Low-protein and low-phosphorus diets had no significant effect on average feed intake per sow,average daily feed intake,and backfat loss,weaning-estrous interval of lactating sows,the estrus rate at 7 days after weaning,the estrous mating rate,and the return rate of the next litter in lactating sows(P>0.05);Low-protein and low-phosphorus diets had no significant effect on total lactation,milk-to-feed ratio,and milk quality of lactating sows(P>0.05);(2)Low-protein and low-phosphorus diets significantly increased the total serum protein content of lactating sows(P<0.05),and significantly reduced the levels of serum urea nitrogen,free fatty acids,and calcium ions(P<0.001).No significant effects of glucose,alkaline phosphatase,IGF-1 and phosphorus levels(P>0.05);(3)Low-protein and low-phosphorus diets had no significant effect on the number of weaning litters,weaning litter gain,average daily weight gain,diarrhea rate,and lactation survival rate of suckling piglets(P>0.05);(4)Low-protein and low-phosphorus diets significantly increased serum albumin and free fatty acid content in suckling piglets(P<0.05).No significant effect on total serum protein,urea nitrogen,glucose,alkaline phosphatase,IGF-1,calcium ions and phosphorus of suckling piglets from sows of different groups(P>0.05);(5)Low-protein and low-phosphorus diets have no significant effect on dominant fecal flora in lactating sows;(6)Low-protein and low-phosphorus diets significantly increased the average nitrogen and phosphorus intake of lactating sows(P <0.05),and significantly reduced faecal nitrogen,faecal phosphorus,urine nitrogen,and total nitrogen emissions from lactating sows(P<0.05);(7)Feeding low-protein and low-phosphorus diets reduced feed cost per sow by3.27 RMB,and reduced feed cost per pig by 0.09 RMB.Collectively,the level of dietary crude protein reduced from 17% to 16% had no significant effects on the performance and reproductive performance of lactating sows,which improved the lactation performance of sows,reduced the emission of urinary nitrogen,and improved production economic benefits.The reduced level of dietary crude protein level from 17% to 16% in combination with reducing the phosphorus level from 0.62% to 0.55%,did not significantly affect the performance,reproductive performance,and lactation performance of lactating sows.However,the low crude protein and phosphorus diet significantly reduced the emission of fecal urine nitrogen of lactating sows,and improved production economic benefits. |
