The effect of delayed first feeding on growth and survival of yellowfin seabream (Acanthopagrus arabicus) larvae

The effect of different initial feeding times (48 h, 72 h, 96 h, and 120 h after hatching) and food deprivation on the point-of-no-return (PNR), survival, and growth of yellowfin seabream Acanthopagrus arabicus larvae were studied under controlled condition. Growth parameters were investigated by evaluating morphometric (head depth, body depth, gut height, musculature height, eye diameter, total length, yolk, and oil globule volume) and gravimetric (dry weight) indices. The larvae commenced to feed exogenously at the mouth opening stage on day 2 after hatching (DAH) and reached PNR between 6 and 7 DAH at 19–20 °C. The time of initial feeding significantly affected the larval growth. From 3 DAH until the end of the trial period at 15 DAH, the growth (all morphometric indices and dry weight) of larvae started which earlier initial feeding start (48 h and 72 h after hatching) were significantly higher than that of 96 h (P < 0.05). Growth parameters were measured until 9 DAH in the larvae commenced feeding at 120 h, since complete mortality was recorded after this sampling point (at 12 DAH). During this period, the larvae showed significantly lower morphometric indices and dry weight compared with larvae in other initial feeding time treatments (48 h, 72 h, and 96 h). Yolk absorption in yellowfin seabream larvae was completed on 4 DAH regardless of the variances in the time of first feeding. Likewise, the oil globule was completely utilized on 5 DAH in all initial feeding trials. No significant differences were noticed in yolk volume and oil globule absorption between different treatments. At the end of the trial at 15 DAH, the survival rate was significantly higher for larvae began first feeding at 48 h (35.67 ± 7.01%) and 72 h (36.48 ± 4.72%) when compared to 96 h first feeding larvae (13.10 ± 2.62%)(P < 0.05). The findings from the current study reveal that the first feeding of yellowfin seabream larvae can be initiated up to 72 h after hatching with no significant differences in growth and survival rate

Digestive function and serum biochemical parameters of juvenile Cyprinus carpio in response to substitution of dietary soybean meal with sesame seed (Sesamum indicum) cake

A feeding trial was designed to evaluate effects of soybean meal replacement (SBM) with sesame seed cake (SSC) at 0 (SSC0), 25 (SSC25), 50 (SSC50), 75 (SSC75), and 100 (SSC100) % in isoproteic (30%) and isolipidic (8%) diets on the growth performance, digestive function and serum and hematological parameters in Cyprinus carpio. Four hundred and fifty common carp juveniles (83.09 g) were randomly distributed into 15 tanks with a flow-through system. Triplicate groups of fish were hand-fed one of the diets to visual satiation thrice daily for 90 days. The survival rate, growth performance and somatic indices did not show significant differences between treatments. Among feed utilization indicators, nitrogen retention efficiency was significantly higher in SSC25 than in other treatments. Lipid retention efficiency significantly increased from SSC50 to SSC100. The number of white blood cells was significantly higher in SSC0 than other treatments. Significantly higher hemoglobin was observed in SSC75 as compared to SS0 and SSC25. Serum biochemical parameters did not significantly differ between dietary treatments. Dietary SSC resulted in significant increase in calcium ADC and activity of digestive trypsin, chymotrypsin, lipase, α-amylase, and alkaline phosphatase. Significantly higher villi height and intestinal muscle layer width were observed in fish fed the SSC75 diet. The villi width in SSC25 and SSC50 was significantly less than in SSC0. Comparable growth performance, feed utilization, apparent digestibility, digestive function, hematological and serum factors indicated the possibility of 75–100% substitution of SBM by SSC in the diet of juvenile C. carpio