In recent years, financial losses due to salinity changes threat bivalve industry. In natural habitat, marine bivalves should be adapted to a series of environmental stressors, including biotic (virus, bacteria and protozoan) and abiotic (salinity, temperature and heavy metal) factors. It is known that salinity fluctuations able to change distribution and vital parameters of bivalves. Suboptimal salinity conditions resulted in changes in defense mechanism, growth, free amino acid, heart rate, oxygen consumption and filtration rate. However, it is necessary to determine the optimal salinity level of cultured bivalves to avoid the risk of mortality and improve growth rate. Therefore, this study aimed to review the findings from various reports in vitro and in vivo conditions which evaluated physiological and immunological responses of different bivalve species submitted to different salinity concentrations. The information of present study is very important in understanding the physiological responses of bivalves, which are living in highly changeable environment such as estuarine.

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The effects of stocking density and environmental conditions on performance, economic profit, carcase characteristics, immunity, and blood plasma parameters of Cobb 500 strain of broiler chickens were evaluated. The 4 climate regions (mild and humid, semi-arid, alpine, hot and dry) and 4 densities (10, 15, 17 and 20 chicks/m 2 ) were carried out as a completely randomised design with 4 Â 4 factorial arrangement of treatments. The corn and soybean based diets were formulated according to the nutrition requirements guide of the Cobb 500 for starter and grower periods. The amount and the composition of the diet were the same for all experimental groups. Growth performance and feed intake were measured weekly. After the injection of sheep red blood cell at 15 and 35 days, blood samples were taken at 24 and 42 days, respectively, to study the immunity of broiler chickens. At the end of the experiment, 3 birds were slaughtered from each experimental unit for measuring the weights of carcase, abdominal fat, gastrointestinal organs (the total weight of gastrointestinal tract and caeca, and liver) and blood parameters. The interaction effects of stocking density and climate region on feed conversion ratio (in starter period), survival rate, cost, profit, cholesterol, triglyceride, high density lipoproteins (HDL), HDL/low density lipoproteins (LDL) ratio, and liver enzymes aspartate aminotranferases (AST), also known as serum glutamic oxaloacetic transaminase (SGOT), and alanine aminotranferase (ALT) were significant (p < .05). Climate and density each had a significant effect on production index (p < .05). The highest production index was obtained in alpine climate. Moreover, the density of 10 chicks/m 2 showed the highest production index. The results showed that rearing Cobb strain chickens in hot and dry climate and at the density of 17 chicks/m 2 had the most economic benefit. Based on the results of this study to achieve the highest profit in different climates, a density of 17 chicks/m 2 (0.633 ft 2 per bird) is recommended for Cobb 500 strain chickens. HIGHLIGHTSNutritional efficiency changes by environmental factors such as climate and stocking density. Obtain sufficient information to combined effect of stocking density and climate on the performance of Cobb 500 broiler chickens. The most reached profit was in the dry climate at a density of 17 chicks/m 2 compared to other climates and densities.

1. The objective of present study was to evaluate the effects of intra-amniotic injection of different probiotic strains (Bacillus subtilis, Enterococcus faecium and Pediococcus acidilactici) on the intestinal MUC2 gene expression, microbial population, growth performance and immune response in broiler chicken. 2. In a completely randomised design, different probiotic strains were injected into the amniotic fluid of the 480 live embryos (d 18 of incubation), with 4 treatments and 5 replicates. Ileal MUC2 gene expression, microbial profile, growth performance and immune response were determined. 3. Injection of probiotic strains, especially B. subtilis, had significant effect on expression of the MUC2 on d 21 of incubation and d 3 post-hatch, but not on d 19 of incubation. 4. Injection of the probiotic strains decreased significantly the Escherichia coli population and increased the lactic acid bacteria population during the first week post-hatch. 5. Inoculation of probiotics had no significant effect on antibody titres against Newcastle disease virus, antibody titres against sheep red blood cell and cell-mediated immune response of chickens compared to control. 6. In ovo injection of the probiotic strains had no significant effect on growth performance of broiler chickens. 7. It was concluded that injection of probiotic bacteria especially B. subtilis into the amniotic fluid has a beneficial effect on ileal MUC2 gene expression and bacteria population during the first week post-hatch, but has no effect on growth performance and immune response in broiler chickens.

This study was carried out to investigate a possible protein‐sparing action of l‐carnitine and ractopamine in rainbow trout, Oncorhynchus mykiss. An 8‐week feeding trial was carried out to evaluate the effects of supplementation of three levels of l‐carnitine (0, 1 and 2 g kg−1) and two levels of ractopamine (0 and 10 mg kg−1) on growth performance, fillet fatty acid compositions and blood biochemical parameters in a 3 × 2 factorial experimental design. Ractopamine and 1 g kg−1 carnitine improved the specific growth rate (1.03% and 1.05% day−1), feed conversion ratio (FCR, 1.3 and 1.29), protein efficiency ratio (PER, 1.88 and 1.85) of fish and crude protein (73.5 and 73.8) content of fish fillet. l‐carnitine and ractopamine increased the levels of albumin, total protein and globulin in the serum of fish. Apart from eicosapentaenoic acid and docosahexaenoic acid, other fatty acids of fish fillet were increased by ractopamine, while total saturated fatty acids were almost intact. However, the total n‐3 poly unsaturated fatty acids were reduced by l‐carnitine supplementation (P<0.05). The present study showed that 1 g kg−1l‐carnitine and 10 mg kg−1 ractopamine each can improve the performance of rainbow trout and their combination in diet could enhance the protein level and change the fatty acids profile in fillet muscle.