Dietary rumen-protected L-arginine or N-carbamylglutamate enhances placental amino acid transport and suppresses angiogenesis and steroid anabolism in underfed pregnant ewes

This study aimed to investigate the effects of dietary supplementation of underfed Hu ewes from d 35 to110 of gestation with either rumen-protected L-arginine(RP-Arg)or N-carbamylglutamate(NCG)on placental amino acid(AA)transport,angiogenic gene expression,and steroid anabolism.On d 35 of gestation,32 Hu ewes carrying twin fetuses were randomly divided into four treatment groups,each consisting of eight ewes,and were fed the following diets:A diet providing 100%of NRC’s nutrient requirements for pregnant ewes(CON);A diet providing 50%of NRC’s nutrient requirements for pregnant ewes(RES);RES diet plus 5 g/d NCG(RES+NCG);or RES diet plus 20 g/d RP-Arg(RES+ARG).On the d 110 of pregnancy,blood samples were taken from the mother,and samples were collected from type A cotyledons(COT;the fetal portions of the placenta).The levels of 17β-estradiol and progesterone in the maternal serum and both the capillary area density(CAD)and capillary surface density(CSD)in type A COT were decreased in response to Arg or NCG supplementation when compared to the RES group.The concentrations of arginine,leucine,putrescine and spermidine in type A COT were higher(P<0.05)in the RES+ARG or RES+NCG group than in the RES group.The mRNA expression levels of inducible nitric oxide synthase(iNOS)and solute carrier family 15,member 1(SLC15A1)were increased(P<0.05)while those of progesterone receptor(PGR)and fibroblast growth factor 2(FGF2)were decreased in type A COT by supplementation with either NCG or RP-Arg compared to the RES group.The results suggest that providing underfed pregnant ewes from d 35 to 110 of gestation with a diet supplemented with NCG or RP-Arg improves placental AA transport,and reduces the expression of angiogenic growth factor genes and steroid anabolism,leading to better fetal development.

Behavioral response of pregnant ewes to high ambient temperature in loose housing system

In order to investigate the behavioral responses of pregnant ewes to high ambient temperature in a loose housing system,eighty-seven pregnant ewes(Chinese little fat-tailed sheep,Ovis aries)from the same loose house were chosen,and nine ewes with the similar body weight and age were marked for later individual behavioral observation.The ambient temperature and relative humidity were recorded,and the individual behaviors of the pregnant ewes were observed continuously from 04:50 to 20:00 once every other day for 14 days.The behavioral state of all the pregnant ewes was recorded once every hour from 5:00 to 20:00,the number of pregnant ewes selecting specific lying areas(designated as area A and area B),was recorded at 15 minute intervals from 12:00 to 17:00 everyday.The final results show that the behavioral durations are significantly different in eating and drinking,rumination,rest,and locomotion for pregnant ewes(P<0.05).The time spent in lying for rumination or rest is significantly longer than that for locomotion(P<0.05).Temperature has a significant effect on the number of pregnant ewes lying on the floor(P<0.05).There are significant differences for pregnant ewes’preference of area A and area B for lying at temperatures ranging from 27.0℃to 31.0℃(P<0.05).The results indicate that the lying behavior is significantly more than the locomotion behavior for the pregnant ewes in the loose housing systems under the high ambient temperature.