The effect of spray-dried porcine plasma and tryptophan on feed intake and performance of weaning piglets

There were three trials involved in this experiment. All piglets in Trial I were randomly distributed into the following 4 treatments. Treatment 1. Corn-soybean diet with 5% SDPP. The tryptophan level was 0.237%. Treatment 2. Corn-soybean diet with 10% meat and bone meal. The tryptophan level was 0.177%. Treatment 3. Treatment 1+0.0662% synthetic tryptophan. The total tryptophan level was 0.303. Treatment 4. Treatment 2+0.0662% synthetic tryptophan. The total tryptophan level was 0.236. Piglets in Trial 2 were distributed randomly into the following 4 treatments. Treatment 1: corn-soybean diet+10% meat and bone meal. The total tryptophan level was 0.176%. Treatment 2: corn-soybean diet+10% meat and bone meal+5% SDPP. The total tryptophan level was 0.180%. Treatment 3: Treatment 1 diet+0.004% synthetic tryptophan. The total tryptophan level was 0.180%. Treatment 4: Treatment 1 diet+0.631% synthetic tryptophan. The total tryptophan level was 0.237%. There were 4 treatments in Trial 3. Treatment 1: corn-soybean diet+10% meat and bone meal. The total tryptophan level was 0.176%. Treatment 2: Treatment 1 diet+0.061% synthetic tryptophan. The total tryptophan level was 0.237%. Treatment 3: Treatment 2 diet+0.061% synthetic tryptophan. The total tryptophan level was 0.298%. Treatment 4: corn-soybean diet+10% meat and bone meal+5% SDPP. The total tryptophan level was 0.180%. The results of Trial 1 showed that the piglets ate significantly more (p < 0.05) when feed included SDPP in the diet during the first 2 weeks. The feed intake also increased when synthetic tryptophan was added in the 5% meat and bone meal diet;, however, the difference did not reach a significant level (p > 0.05) during the first 2 weeks. Three weeks onwards the feed intake of 5% meat and bone meal treatment was significantly lower (p < 0.05) than for the other three treatments. The results of Trial 2 showed that the feed intake could be significantly improved only when the total tryptophan level reached 0.237%. Piglets in the 5% SDPP treatment had higher feed intake than piglets in 10% meat and bone meal treatment with 0.180% of tryptophan, but did not reach a significant level (p < 0.05). Body weight gain also had the same trend as feed intake. The pigs in Treatment 1, the lowest total level of tryptophan treatment (0.176%), had lowest feed intake and weight gain, but the difference did not reach a significant level (p > 0.05). The pigs in Treatment 1 of Trial 3 had the lowest feed intake and weight gain (p > 0.05). Treatment 2 (0.237%) had the highest average feed intake from Week 1 to Week 5; the second best result was recorded in Treatment 4. As for the weight gain of the piglets in Treatment 4 (5% SDPP), they had a higher average weight during the first 3 weeks. The feed efficiency was better for Treatment 4 (5% SDPP) during the first 2 weeks. The results of these trials showed that both SDPP and tryptophan had a trend to improve the feed intake and weight gain.