Lucas Pimentel Bonagurio

This study aimed to estimate the standardized ileal digestible leucine intake (SID-Leu_i, mg) in laying hens for maintenance, and to describe the response in laying hens to SID-Leu_i, thereby providing the information required to determine the optimum economic intake of SID-Leu for laying hens. Two nitrogen balance series, one balanced and the other unbalanced with respect to leucine (Leu), were used to estimate the SID-Leu requirement for maintenance using 36 roosters per series. The roosters were randomly distributed among the six levels of Leu with each level being replicated six times. The six diets were formulated to contain 0.0, 3.5, 6.9, 10.4, 13.9, or 17.4 g/kg of SID-Leu for the unbalanced series and 0.0, 4.0, 8.0, 12.0, 16.0, or 20.0 g/kg of SID-Leu for the balanced series. The SID-Leu_i maintenance requirement was calculated as 144 mg/bird d, 66 mg/kg d, 74 mg/kg^0.75d or 395 mg/BP_m^0.73d. For the response trial, 120 individually caged laying hens (63 weeks old) were randomly distributed among eight treatments with 15 replicates. To estimate the SID-Leu_i for the population of hens, the Reading Model was fitted to the data using body weight (BW, kg), SID-Leu_i and egg output (EO, g). The Reading Model calculated the mg SID-Leu_i = 11.6 EOmax + 43.4 BW. The efficiency of SID-Leu utilization for laying hens was estimated to be 79%.

This study assessed the effect of different periods of post-hatch fasting on animal performance and breast and digestive system growth in European quail. Quail chicks were distributed in a completely randomized design, with four fasting periods (0, 24, 36, and 48 hs) and four replications of 40 birds per treatment. In 1 to 14-day-old chicks, weight gain decreased with increasing fasting time. Compensatory gain was observed from 15 days of age onward. Fasted quail had a lower length and relative weight of the digestive system than fed animals for up to 14 days. Histologically, the duodenal villus height was significantly lower in 3-day-old quail fasted for 36 hs than in those fasted for 48 hs, but this effect was not observed at 7 days. Scanning electron microscopy showed no differences in the small intestinal mucosa between fasted and fed birds at 3 days of age. Post-hatch fasting reduced the relative weight of the breast in quail aged 1 to 14 days but did not affect type IIa and IIb fiber diameter at 35 days. On the basis of these results, it is recommended that European quail raised for meat should not be fasted for more than 48 hs post-hatch.

This study evaluated the effect of oral supplementation with tryptophan (Trp) and pyridoxine (Pyr) on the growth performance and social behavior of suckling piglets before and after weaning. At day 14, six suckling piglets per sow were distributed into three treatments and allotted in a randomized block design, with eight replicates and two piglets per experimental unit. Treatments consisted of a Control - oral supplementation with L-alanine (1.70 g), D-glucose (1.74 g) and distilled water (3.44 mL); Trp - oral supplementation with Trp (3.5 g/d) and distilled water; and Trp + Pyr - oral supplementation with Trp (3.5 g/d) + Pyr (0.0095 g/d) and distilled water. Each treatment was supplied orally five times per day (2.5 mL each treatment), from 14 to 21 days old. Piglets were monitored continuously in the nursing phase for 24 h at 21, 28 and 33 days of age to assess the behavior (standing, lying, eating, socializing, sitting and drinking). Piglets receiving oral Trp + Pyr showed a decreased weight loss on the first day after weaning (P = 0.03). Performance was not affected (P > 0.05) by treatments in each studied period, such as in overall period (21 to 34 days) after weaning. Piglets receiving Trp supplementation visited the feeders more frequently from days 21 to 22 (P < 0.01) and from days 28 to 29 (P < 0.02), as well as in the overall period (P < 0.01). It is concluded that high doses of tryptophan with or without high doses of pyridoxine, supplied orally to nursing piglets, reduced the weight loss on the first day after weaning and increased the frequency of visits to the drinkers on the first day after weaning and also to the feeders, mainly from weaning until 7 days after.

Effects of vitamin B6 and tryptophan on pork quality and amount of lean meat in gilts of 70–100 kg bodyweight