BACKGROUND: In recent years, many studies have been conducted on finding a suitable replacement for fish meal to supply the needs of aquaculture feed industry. Objectives: The present study was performed to examine the effect of replacing fish meal and fish oil with plant sources on bacterial counts in intestinal contents and mucus and bacterial composition in Beluga sturgeon. Methods: Beluga sturgeons with a mean initial weight of 133±5 g were distributed into 18 (300 L) tanks (30fish/tank) and were fed experimental diets for 60 days. The control diet contained only fish meal and fish oil as the primary source of protein and lipid, while the experimental diets contained 0, 40, 60, 80 and 100 percent plant protein sources (wheat gluten, corn gluten and soybean meal) and 20% vegetable oil blend (canola, sunflower, cotton and safflower oils) respectively. Results: Results showed that replacement of 80% fish meal and fish oil with plant sources didn’t have significant effect on final weight (235 ± 17 g) compared to control group (256.1 ± 10 g) in a 60 days trial. Replacement of fish meal with 100% plant proteins in combination with 80% vegetable oils resulted in significantly lower final weight (225.7 ± 11 g), compared to other treatments including control group (p<0.05). Replacing 80% fish oil with vegetable oils resulted in a significant reduction of bacterial count in intestinal contents and a significant increase in percentage of Entrobacteriacea sp. However, no significant differences were detected in bacterial counts of mucus in experimental treatments compared to control (p>0.05). Replacement of 60, 80 and 100% fish meal and 80% fish oil with plant sources significantly decreased bacterial counts in intestinal contents and intestinal mucosa compared to control group (p<0.05). Also this replacement cause significant change in bacterial composition of intestine. Conclusions: The results suggested that using plant sources in juvenile Beluga sturgeon diet decreases the bacterial count in the intestinal contents and mucus and changes the composition of intestinal micro flora.

BACKGROUND: Tilapia, Oreochromis niloticus, is an omnivorous and important breeding species in the world. Over the recent years, tilapia breeding has begun in Iran. In aquaculture, it is very important to regulate a balanced diet in terms of nutrients needed for growth, which would be also economically appropriate.OBJECTIVES: The main objective of this study was to investigate the effect of substituting chicken waste powder in the diet of fish at levels of 0, 25, 50, 75, and 100 % on the tissue structure of different parts of the intestine of Nile tilapia.METHODS: 75 fish (three frequency per treatment) were fed with chicken waste powder instead of fish meal in their diet for eight weeks at 0, 25, 50, 75, and 100 % levels. At the end of the treatment, separate samples were taken from the initial, middle, and end parts of the intestine. After passing the usual histological steps, the slides were assessed by hematoxylin-eosin staining and TUNEL immunohistochemistry technique.RESULTS: In histometric studies, the highest villi height, thickness, muscle layer, and number of goblet cells were reported in the control group and the lowest in the 100 % group. In immunohistochemical studies, the number of apoptotic cells in groups 75 and 100 % was higher than that in the other groups.CONCLUSIONS: According to the results of the present study, it could be suggested that the replacement of chicken waste powder instead of a fish meal up to 50 % for indigo tilapia is tolerable. However, higher levels of chicken waste powder will reduce absorption, and acceptance of food and have adverse effects on growth.

Objective: Quail production is ranked as an important alternative animal protein source in Cameroon. One of the main constraints of this production is the quality of feed, which lacks pro¬tein that is regularly supplied by fish meal. To avoid disagreements due to the constant shortage of fish meal, alternative protein sources are needed, and among them are crickets (Acheta domes¬ticus). The goal of this study was to find out how well Japanese quails could be raised if fish meal was replaced with cricket meal. Materials and Methods: A total of 192, 4-week-old quails were divided into 12 similar sets of 8 females and 8 males. The Four experimental diets (T00, T15, T30, and T45) were all formulated based on the level (0%, 15%, 30%, and 45%, respectively) of fish meal substitution with cricket meal in the basal diet (crude protein: 20.18% and ME: 3,013.78 kcal/kg) and randomly assigned to three sets in a completely randomized design consisting of four treatments each repeated three times. Growth, carcass, and some reproduction parameters were collected. The data were analyzed using one-way analysis of variance and the Duncan test, with a significance level of 5%. Results: Cricket meal diets increased body weight in males (204.32 ± 5.69 gm for T45) and regard¬less of the sex (226.72 ± 29.45 gm for T30) compared to 184.17 ± 3.11 gm and 214.55 ± 32.77 gm for the control group, respectively. In females, substitution at 30% increased body weight (253.80 ± 6.48 gm), while 45% induced a reduction (216.67 ± 6.49 gm) when compared to the control group value (244.92 ± 6.07 gm). Carcass yield and the proportion of different parts were not significantly affected by the experimental diets. Liver proportions were significantly higher at 15% and 35% cricket meal incorporation compared to 45%. First songs and egg laying were recorded at 7 weeks with T15, which also led to improved egg laying performance compared to the other treatments. Ovaries were poorly developed in the T45 females compared to the other treatments. Conclusions: Cricket flour might be a good candidate as a locally available protein source to sub¬stitute fish meal in the Japanese quail's diet at the finisher and reproductive stages, and the level of 30% seems to be more efficient. [J Adv Vet Anim Res 2022; 9(2.000): 310-322]