Milchleistung sowie Milchfett- und -energiegehalte bei Sauen mit unterschiedlicher Methioninversorgung

Studies on the tryptophan requirement of lactating sows. Part 1: Estimation of the tryptophan requirement by performance

Mature sows were evenly assigned to six dietary treatments, which differed only in the concentration of total (apparent ileal digestible, AID) tryptophan (Trp) amounting per kg feed to 1.2 g (0.8 g) to 4.2 g (3.8 g) in diets 1-6. For a total of 72 lactations (28 days) sows' feed intake was measured daily and body weight was measured on day 110 of pregnancy and on days 1 and 28 of lactation. Litter size was standardized to 10-12 piglets within 1 week after farrowing. The piglets were weighed at days 1, 21 and 28. Milk yield was recorded by the weigh-suckle-weigh method on days 20 and 21. Concentrations of milk fat and protein were measured in manually drawn samples (days 20 and 21) by infrared spectroscopy. Average daily feed intake of the sows was 3.4, 4.7, 4.7, 6.1, 5.1 and 4.7 kg (diets 1-6 respectively, p < 0.001). Body weight losses of the sows during lactation were 30.8, 16.9, 19.2, 9.5, 14.1 and 13.1 kg (diets 1-6 respectively, p < 0.05). Milk output in the average of days 20 and 21 was 6840, 8192, 8362, 9035, 8618 and 8140 g/day, respectively (p < 0.01). There were no differences in milk fat or protein contents. Daily weight gain of the piglets in the average of lactation was 157, 184, 184, 187, 185 and 177 g, respectively (p < 0.10). Based on the results of this study the estimated Trp requirement of lactating sows for optimal performance was calculated with 1.9 g AID Trp/kg in the lactation diet (according to 2.0 g true ileal digestible Trp and approximately 2.6 g Trp on total basis).

Effects of L-carnitine supplementation on milk production, litter gains and back-fat thickness in sows with a low energy and protein intake during lactation

The present study investigated the effect of L-carnitine supplementation during pregnancy (125 mg/d) and lactation (250 mg/d) on milk production, litter gains and back-fat thickness in sows fed a low-energy and low-protein diet during lactation. Sows supplemented with L-carnitine produced more milk on days 11 and 18 of lactation (+18 %; P<0.05) and had higher litter gains during suckling (+20 %; P<0.01) than control sows. Loss of body weight during lactation was similar in both groups, but sows supplemented with L-carnitine had a greater reduction of back-fat thickness (+45 %; P<0.05) during lactation than control sows. In conclusion, this study shows that L-carnitine increases milk production and litter gains in sows in a strongly negative energy and N balance, and enhances body fat mobilisation.

Supplementation of sows with L-carnitine during pregnancy and lactation improves growth of the piglets during the suckling period through increased milk production

Recent studies showed that piglets of sows fed diets supplemented with L-carnitine grow faster during the suckling period than piglets of control sows fed diets without L-carnitine. This study was undertaken to investigate the effect of L-carnitine supplementation in sows on milk production and milk constituents. An experiment was performed in which two groups of 20 gilts each were fed diets with or without supplemental L-carnitine during pregnancy (0 vs. 125 mg L-carnitine daily/sow) and lactation (0 vs. 250 mg L-carnitine daily/sow). The experiment was continued over two reproductive cycles. L-carnitine-treated sows had larger litters (P<0.01) and higher litter weights (P<0.05) than control sows. Piglets of L-carnitine-treated sows had lower birth weights (P<0.05) but grew faster during the suckling period (P<0.01) and were heavier (P<0.05) at weaning than piglets of control sows. L-carnitine-treated sows had higher milk yields on d 11 and 18 of lactation than control sows (P<0.05). Milk of L-carnitine-treated sows had higher concentrations of total and free carnitine than milk of control sows (P<0.001); concentrations of fat, protein and lactose and the amounts of gross energy in the milk did not differ between the two groups of sows. The amounts of protein (P<0.05) and lactose (P<0.05) were higher in L-carnitine-treated sows than in control sows; the amount of energy secreted with the milk tended to be higher in carnitine-treated sows than in control sows (P<0.10). The study suggests that piglets of carnitine-treated sows grow faster during the suckling period than those of control sows because they ingest more nutrients and energy with the milk.