RESUMO
The present study was to evaluate the effect of trace minerals (Zn, Mn, and Cu) from complexed amino acid minerals (ZMCAA) and bis-glycinate chelated minerals (ZMCGly) in laying hen diets on performance, internal and external egg quality, yolk mineral deposition, intestinal morphometry, and bone characteristics. From 78 to 98 weeks of age, 400 White LSL-Lite strain laying hens were distributed in a randomized design with 4 treatments with 10 replicates per treatment. Treatments were distributed in a 2 × 2 factorial arrangement using either Zn, Mn, and Cu of ZMCAA or ZMCGly source at 2 levels: low (20, 20, and 3.5 mg/kg of Zn, Mn, and Cu, respectively) or high (40, 40, and 7 mg/kg of Zn, Mn, and Cu, respectively). The analysis of variance was performed, and in cases where differences were observed, the means were compared using Tukey's test (P < 0.05). The source and level of trace mineral supplementation had a significant impact on the performance of laying hens. Hens fed ZMCAA had higher egg production (P = 0.01), egg weight (P = 0.02), egg mass (P = 0.01), and lower feed conversion ratio (P = 0.05) compared to those fed ZMCGly. The ZMCAA supplementation showed higher albumen height (P = 0.01), albumen weight (P = 0.01), and eggshell thickness (P < 0.01). The deposition of Zn (P < 0.01), Mn (P < 0.01), and Cu (P < 0.01) in the egg yolk was greater for hens received ZMCAA. Tibia weight (P = 0.04) and bone densitometry (P < 0.01) in the tibia were higher with ZMCAA supplementation. In the small intestine, ZMCAA resulted in longer villi (P = 0.02) and shorter crypt depth (P = 0.01) in the duodenum. Jejunum and ileum measurements were influenced by the level and source of trace minerals (P < 0.05). Laying hens fed ZMCAA exhibited superior performance, egg quality, deposition of trace minerals in the egg yolk, and bone density compared to hens fed ZMCGly. In this study, older laying hens supplemented with ZMCAA at lower levels demonstrated adequate levels of supplementation.
RESUMO
The objective of this study was to evaluate the effects of different levels of digestible lysine, at fixed amino acid ratios, in performance, blood parameters and diet digestibility of barrows from 15 to 30 kg. Fifty barrows of the Duroc breed with an average initial body weight of 14.95±3.22 kg were assigned to five treatments in a completely randomized experimental design with five replicates and of two animals per experimental unit. Treatments consisted of crude protein and lysine levels, maintaining a fixed ratio with the other digestible amino acids (8.4, 9.4, 10.4, 11.4, and 12.4 g kg-1lysine/kg of diet). The feed conversion decreased linearly according to lysine levels. The apparent digestibility coefficients of dry matter and crude protein increased linearly, and the same response was observed for serum total protein and urea. The results indicate that digestible lysine level for Duroc barrows in the starter phase is 12.4 g kg-1 of diet, as it improved feed conversion ratio and apparent nutrient digestibility.
