We compared the effects of supplementing L-lysine??SO4 to L-lysine??HCl on growth performance, nutrient digestibility and nitrogen retention in weaning pigs. A total of 96 crossbred pigs, weaned at 21?? days of age and with an average initial body weight (BW) 6.23??.01 kg, were given one of 4 treatments, which translated into 6 replicates of 4 pigs in each pen. The animals were randomly assigned to four dietary treatments according to a randomized completely block design (RCBD) as follows: 1) control-no synthetic lysine, lysine deficient (0.80% total lysine); 2) L-C (= 0.2% L-lysine??HCl); 3) K-L-S (= 0.332% L-lysine??SO4, A company); 4) C-L-S (= 0.332% L-lysine??SO4, B company). Diets were formulated with corn, soy bean meal, and corn gluten meal as the major ingredients, and all nutrients except the lysine met or exceeded NRC requirements (1998). The lysine content of supplemented synthetic lysine was the same in all treatment groups except the control. No clinical health problems associated with the dietary treatments were observed. During the entire experimental period, body weight, average daily gain (ADG) and feed efficiency (G:F ratio) increased (p<0.01) in pigs fed the experimental diets supplemented with L-lysine??HCl or L-lysine??SO4 produced by A company, irrespective of the two synthetic lysine sources. Although the supplementation of L-lysine??SO4 produced by B company tended to improve the ADG and G:F ratio, significant differences were not seen among all treatments and tended to be lower than the L-C (L-lysine??HCl) and K-L-S (L-lysine??SO4 groups using the product from A company). The digestibility of crude protein (CP) was increased by the supplementation of synthetic lysine (p<0.05), irrespective of the L-lysine source (L-C, K-L-S, C-L-S). The results of this study showed that ADG, G:F ratio, and CP digestibility improved when L-lysine??SO4 or L-lysine??HCl was supplemented into the weaning pigs' diet. There was a clear difference in efficacy between the two lysine??SO4 products based upon the growth performance of weaning pigs. Consequently, the bioavailability of lysine??SO4 products should be evaluated before supplementation of synthetic lysine in swine diets.
Asian-Australasian Association of Animal Production Societies(AAAP)
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