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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.

Variance components and heritabilities for daily weight gain (DWG) were estimated for Nile tilapia farmed in cages across nine generations (G1-G9) of selection in a breeding program in Brazil. DWG was measured in 16,272 accumulated tagged animals representing 535 full- and half-sib families of Nile tilapia under cage farming. The additive genetic variance showed a slight variation (0.051-0.066), and heritability estimates ranged from 0.20 to 0.33. The common environmental effect accounted for a higher proportion of the total variance in DWG, especially in the last generations (6%-24%). A genetic trend based on all data available showed a substantial increase in the DWG (about 3.3% per generation) of Nile tilapia across nine generations of selection. Furthermore, our results demonstrate ample scope for further genetic improvement., (© 2021 Wiley-VCH GmbH.)

The objective of this study was to evaluate the development and growth of the digestive system organs, from the 11th day of incubation until the 14 d post-hatch in European and Japanese quail. On days 11, 13 and 15 of incubation at hatch and at 4, 7, 10 and 14 d post-hatch, embryos or chicks of European and Japanese quail were analyzed. After 15 d of incubation, samples from stomach and small intestine were analyzed by microscopy. European quail had significantly heavier body weight at 15 d of incubation and after 4 d post-hatch. The digestive system weight progressively increased with age and was similar between European and Japanese quail at 11, 13, and 15 d of incubation and 10 d post-hatch, while relative weight of digestive system was similar between quail type with great values at 4 d post-hatch. For relative weight of the small intestine + pancreas, the weight of the proventriculus and of the gastric ventricle increased significant by among ages analyzed in both types of quail. At hatch, proventriculus had functional secretory cells and mucosa of gastric ventricle had a thin coilin membrane. In small intestine segments, at 15 d of incubation the height of the villi was similar among duodenum, jejunum, and ileum (80 μm). Villi had elongated shape towards the intestinal lumen, covered by enterocytes and dispersed goblet cells with PAS+ and AB+ contend in all segments. The number of goblet cell/villi increased in segments until 7 to 10 d post-hatch. Duodenum increases the villi up to 14 d, while the jejunum and ileum up to 10 and 4 d, respectively. Based on our data in digestive system growth, a shorter period of post-hatch fast and specific diets to quail during first days of growth is recommended to both quail types. It is concluded that the development and growth of different organs of the digestive system up to 14 d of age was similar between European and Japanese quail., (© 2018 Poultry Science Association Inc.)