Effect of Adding Aroma Agent During Late Pregnancy and Lactation on Reproductive Performance and Intestinal Microbiota in Sow (Preliminary Report)

Effect of Adding Aroma Agent During Late Pregnancy and Lactation on Reproductive Performance and Intestinal Microbiota in Sow (Preliminary Report)

Abstract: China is the largest pig producer and pork consumer in the world, and the average reproductive performance of sows in China is obviously lower than that in（of） developed countries such as countries in Europe and America. Therefore, it is particularly important to improve the reproductive performance of pigs and the efficiency of pig industry. Adding aroma agents to feed can improve the feed intake and growth performance of piglets and growing-finishing pigs, but whether aroma agent can improve the feed intake and reproductive performance of lactating sows remains to be studied. Intestinal microorganisms are affected by the host's physiological state, diet, diseases and the use of antibiotics. There are many physiological changes in sows from late pregnancy to lactation, which may affect the intestinal microorganisms of sows, and the changes of intestinal microorganisms may affect the reproductive performance of sows. Therefore, it is of great significance to study the change patterns of intestinal microorganisms in sows in the late pregnancy and lactation period for pig production. In the experiment, 20 large white sows were randomly divided into two groups, with 10 replicates in each group and 1 sow in each replicate. The control group (CON) sows were fed with basal diet, while the test group (FLA) sows were fed with basal diet +1000 g/t (of) aroma agent. The test period was from the day 90 of sow pregnancy to the day 25 after delivery, and piglets were weaned on the day 25 after birth. The test results showed that: (1) Compared with the control group, adding aroma agent to diet increased the birth weight (P<0.05), weaning weight (P<0.05) and litter weight gain (P<0.05); In addition, compared with the control group, the average daily feed intake of sows and the average daily gain of piglets in test group increased by 4.69% (P=0.09) and 9.52% (P=0.06) respectively. There was no significant difference in sow backfat thickness, litter size and cross-fostering weight of piglets between two groups (P>0.05). (2) Adding aroma agent to diet and different reproductive stages affected the composition of intestinal microorganisms in sows at the phylum level and genus level. The results of Spearman correlation analysis showed that the relative abundance of the Phascolarctobacterum was positively correlated with the average daily feed intake of sows during lactation and the weight gain of piglets (P<0.05). Similarly, the relative abundance of Norank_f_Muribaculae was positively correlated with the average daily feed intake of sows (P<0.05). However, the relative abundance of Unclassified_F_Lachnospiraceae was negatively correlated with litter weight gain and average daily gain (P<0.05). In addition, the relative abundance of Clostridium_sensu_stricto_1 was negatively correlated with piglet litter weight gain (P<0.05). To sum up, adding aroma agent to diet can regulate the microbial composition of sow intestine, which may be beneficial to increase the average daily feed intake of lactating sows (7.44 kg vs 7.11 kg), the birth weight, weaning weight and weaning litter weight gain of piglets.

Feed intake determines the intake of nutrients, which must first meet the maintenance needs of the body and then be used for production, so insufficient feed intake will seriously affect the production performance of pigs. The feed intake is affected by animal genetic factors, health status, feeding management, diet nutrition level and palatability. Feed flavoring agent can improve the palatability of feed and increase feed intake of animals to a certain extent. Commonly used feed flavoring agents include aroma agent, sweetener and umami enhancer(freshness agents.). Studies have shown that adding aroma agent to feed can improve the feed intake and growth performance of piglets and growing-fattening pigs.

The purpose of this test was to explore the effect(effects) of adding aroma agent to diet on reproductive performance of lactating sows, and the effect(effects) of adding aroma agent to feed at different physiological stages on intestinal microorganisms of sows, so as to provide reference data and theoretical basis for improving reproductive performance of sows.

1.2 Test design and diet

Single factor test design was used in the test, and 20 healthy large white sows with similar backfat thickness and delivery date were randomly divided into two groups, with 10 replicates in each group and one sow in each replicate. The sows in the control group were fed with basic diet of sows (Table 1), and the test group was fed with test diet (basic diet of sows +1000 g/t aroma agent). The test started from day 90 of sow pregnancy to day 25 postpartum when piglets are weaned. Refer to NRC 2012 for the diet preparation, and see Table 1 for the diet formula and nutritional components.

1.4 Determination indicators and methods

Record the feed intake of sows during lactation and calculate the average daily feed intake; Record the number of live newborn piglet, birth weight and weaning weight, and record the newborn litter birth weight, weaning litter weight and average daily gain of piglets. Changes of sow's backfat: On day 100 pregnancy and day 25 after delivery, the thickness of sow backfat at P2 point (6 cm from the left side to the last costal back midline) was measured by ultrasonic backfat tester (Ami Hand Scan), and the sow backfat loss during lactation was calculated. Changes of microbial flora: On day 100 of pregnancy and day 14 of lactation, rectal fecal samples of five sows in each group were randomly collected and stored at -80℃. Extract fecal microbial DNA and carry out PCR amplification, HiSeq PE250 sequencing and data analysis.