Avaliação de diferentes fontes e níveis de metionina em dietas para suínos em crescimento e terminação durante o verão

Abstract

The aim of this study was to compare the effects of different sources (DL-Met or DLHMTBA) and levels of methionine on the performance, metabolic status, and carcass characteristics of growing and finishing pigs during the summer. Forty-four pigs (castrated males and females; TN70® * Duroc® genetics) were used, distributed into 4 treatments in a 2x2 factorial design, with two sources and two levels of methionine: HMTBA (84%) vs. DL-Methionine (DL-Met); 100% vs. 120% in the lysine ratio recommended by the breed's feeding manual. The animals were distributed in randomized blocks (according to sex, weight, and litter origin), with each treatment consisting of 11 replicates, where the pig was considered the experimental unit. The data were subjected to analysis of variance using the PROC MIXED procedure in SAS. The model considered fixed effects of sources, levels, and the interaction between factors. A p-value < 0.05 was considered significant, while values 0.05 ≥ p ≤ 0.10 were considered a trend. In phase 3, animals that received the HMTBa source showed higher values for average daily gain (ADG) and total weight gain (TWG) (p < 0.05) compared to those that received DL-Met. In phase 4 and over the entire period, there was an improvement in TWG, ADG, and final weight (FW) (p < 0.05) for animals that received HMTBa. A higher value for carcass length (p < 0.05) was observed for the use of the HMTBa source. The level within the requirement (100%) resulted in the best values for feed conversion (FC), total feed intake (TFI), ADG, TWG, and FW (p < 0.05) when compared to the treatment at the 20% higher level. The same effect was observed for carcass characteristics, where better values were presented for shoulder weight (PPAle), carcass meat yield (RendCC), carcass meat quantity (QCC), carcass lean meat quantity (QCMC), carcass lean meat percentage (PORCCMC), loin weight (Plombo), ham weight (PPER), and lower backfat thickness of the last rib ETUC (p < 0.05). For redox status, levels within the requirement provided higher plasma concentrations for glutathione-S-transferase and vitamin E (p < 0.05). A significant interaction was observed between sources and levels (p < 0.05), where the HMTBa source showed better GPT and GMD indices, regardless of the levels, while DL-Methionine showed a worsening for these variables when supplementation exceeded requirements. This interaction effect also occurred for ham weight (p < 0.05). The results indicate that the use of HMTBa provided better results than the use of DL-Met for the performance and carcass characteristics of pigs in the summer, while high levels of DLMet compromised performance. The difference in the efficiency of use of the two sources seems to be related to their chemical and metabolic properties.