Effects of Maternal Nutrition and Rumen-Protected Arginine Supplementation on Postnatal Lamb Performance and Organ Mass
Our hypothesis was that rumen-protected arginine supplementation would overcome the negative effects of restricted maternal intake during the last two-thirds of gestation on lamb organ mass and postnatal performance. To investigate the effects that arginine supplementation would have, n = 32 multiparous, Rambouillet ewes were allocated to one of 3 treatments in a completely random design at 54 ± 3.9 d of gestation. Dietary treatments included either 100% of requirements (control, CON), 60% of control (restricted, RES), or RES plus a rumen-protected arginine supplement dosed at 180 mg/kg BW once daily (RES-ARG). Ewes were penned individually in a temperature controlled facility, and remained on these treatments through parturition. Upon parturition, lambs were immediately removed from their dam and reared independently. At 54 ± 3 d of age, lambs were necropsied and organs were dissected. Birth weights in lambs from CON ewes were greater (P = 0.04) than lambs from RES ewes, with lambs from RES-ARG ewes being intermediate (5,373, 4,553, and 4,697 ± 256.0 g, respectively). At 54 ± 3 d of age, curved crown rump measurements were longer (P = 0.003) in lambs from RES-ARG ewes than from RES, with a tendency for lambs from RES-ARG ewes to also be longer (P = 0.06) than CON (99.8 vs. 93.9 vs. 96.3 ± 1.28 cm, respectively). Organ mass measurements showed lambs from RES-ARG ewes had greater (P = 0.05) liver mass than RES, with lambs from CON ewes being intermediate (490.0 vs 481.2 vs. 429.5 ± 21.08 g, respectively). In addition, lambs from CON ewes had greater (P = 0.01) mass of adrenal glands than lambs from RES ewes. These data support that rumen-protected arginine supplementation may partially mitigate negative effects on postnatal lamb performance and organ mass due to restricted maternal intake during the last two-thirds of gestation.
Keywords: arginine, developmental programming, offspring