Effects of Supplementary Feeding of Italian Ryegrass on the Reproductive Performance, Levels of Stress Hormones, Body Temperature, Fecal Score and Fecal Microbiota in Primiparous Sows and in Piglets

Abstract Text: The supply of a fiber diet during the gestation period has been known to prepare pregnant animals to ad libitum feeding during lactation to meet nutrient requirements for maintenance and milk production. This study was conducted to evaluate the effect of dietary Italian ryegrass supplementation on the reproductive performance, levels of stress hormones, body temperature, fecal score and gut microbial shedding in primiparous sows and piglets. Three week after pregnancy, a total of 80 sows (Landrace × Yorkshire; parity = 1) were randomly allocated to two treatments (40 sows per treatment): 1) CON, basal diet; 2) F, basal diet, adding enough Italian ryegrass (IRG) in another feeder (sows can access to IRG ad libitum). Dietary treatments were fed until 1 week before farrowing. Piglets were weaned at d 28. Results showed that supplementation of dietary fiber did not affect reproductive performance of sows. During d 14 to 21 after farrowing, the ADG of the piglets from sows supplemented fiber was higher (P<0.05) than that from CON. Norepinephrine levels were lower (P<0.05) in sows with IRG supplementation at d 50 and 108 of gestation compared to those in the CON, while cortisol levels were observed to be lower only during d 108 of gestation in IRG supplemented sows (P<0.05). No effect was observed on the rectal temperatures of the gestating sows and piglets. No effect was further observed on the stress hormone levels, fecal scores and microbial shedding in piglets. In conclusion, dietary supplementation of extra IRG to primiparous sows before delivery may reduce the stress level of primiparous sows during the 1^st trimester of gestation and contribute to improving growth performance of piglets.

Table 1. Effect of feeding supplementation of Italian Ryegrass on performance in sows and piglets
Items	Date/Period	CON	F	SE
Litter size	At birth	10.7	11.0	1.0
	At weaning	10.2	10.6	0.9
Piglet average BW, kg	At birth	1.41	1.43	0.06
	At weaning	7.47	7.71	0.20
Piglet ADG, kg	D 14 to 21	0.236b	0.248a	0.008
Sow norephineprin, pg/mL	D 50 of gestation	87.3a	79.1b	7.0
	D 108 of gestation	76.3a	64.7b	5.9
Sow cortisol, µg/dL	D 108 of gestation	2.4a	1.8b	0.3

 Keywords: Italian ryegrass, reproductive performance, sow