A brief review of the methodology and cryoprotectants in selected fish and mammalian species.

Cryopreservation is a valuable technique used to assist in the genetic improvement of cultured stocks and provide a continuous supply of good-quality semen for artificial insemination. Conserving semen by cryopreservation serves several purposes (e.g. artificial reproductive technologies and species conservation) and is also used in the clinical treatment of human infertility. However, the lifespan of cryopreserved semen is influenced by a range of factors, including storage temperature, cooling rate, chemical composition of the extender, the concentration of cryoprotectant, reactive oxygen species, seminal plasma composition and hygienic control. The choice of cryoprotectant is a vital factor underlying the success of animal semen cryopreservation. In this regard, extensive research has been carried out on various cryoprotectants, such as egg yolk, dimethyl sulfoxide, methanol, ethylene glycol and dimethylacetamide. Recent studies have also described the use of a range of new cryoprotectants for cryopreservation, including compounds of plant origin (soy), amino acids, antifreeze proteins, carbohydrates and cyclodextrins. Moreover, semen cryopreservation and storage require the use of liquid nitrogen or ultralow refrigeration methods for both long- and short-term storage. This review summarizes the general methods used for freezing semen and discusses the use of traditional and newly emerging cryoprotectants (permeable and non-permeable) for the cryopreservation of semen in selected fish and mammalian species.

Supplementation of Siberian sturgeon (Acipenser baerii) diet with different zinc sources: effects on growth performance, digestive enzymes activity, hemato-biochemical parameters, antioxidant response and liver histology.

An 8-week feeding trial was carried out to examine the effect of different sources of dietary Zn on some physiological responses (performance, digestive enzymes activity, hemato-biochemical parameters, antioxidant status and liver histology) of Siberian sturgeon, Acipenser baerii. For this purpose, fish with an average weight of 100 g ± 5 were randomly allocated into four groups including control, inorganic zinc (Zn-sulfate), organic zinc (Zn-gluconate), and zinc-oxide nanoparticles (ZnO-NPs) at 50 mg Zn kg- 1 feed. Improved growth indices, namely weight gain (WG) and specific growth rate (SGR) and feed conversion ratio (FCR) were observed in fish fed Zn-gluconate supplemented diet (P < 0.0.5). The highest digestive enzymes activity was recorded in fish fed Zn-gluconate supplementation (P < 0.0.5). Hematological indices significantly increased in fish fed diet containing ZnO-NPs (P < 0.0.5). Serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) of fish fed ZnO-NPs contained diet were the highest (P < 0.0.5). The highest serum superoxide dismutase (SOD) and catalase (CAT) enzymes activity were observed in fish fed ZnO-NPs and inorganic/organic Zn contained diets, respectively. While liver tissue SOD and glutathione peroxidase (GPx) enzymes activity Zn were significantly increased in fish fed inorganic/organic Zn supplemented diet (P < 0.0.5). Based on liver histological results, a severe tissue changes such as necrosis and pyknosis were observed in fish fed with Zn-sulfate in comparison to other forms. In conclusion, the data of the present study confirmed that organic Zn (mainly) and nano-Zn (to some extent) could be more efficient Zn sources in Siberian sturgeon.

Impact of dietary curcumin administration along with feed-born silver nanoparticle on growth, hemato-biochemical parameters, and digestive enzyme activity of common carp (Cyprinus carpio).

This research explored the impacts of feed-born silver nanoparticles (AgNPs) on common carp (Cyprinus carpio) and whether dietary curcumin supplementation could ameliorate the impacts of AgNPs on growth, hemato-biochemical parameters and digestive enzyme activity. Nine experimental diets were prepared containing 0.00, 0.05, and 0.15 g kg-1 AgNPs, as well as 0.00, 0.75, and 1.50 g kg-1 curcumin in a factorial design. Triplicate groups of common carp (4.82 ± 0.41 g) were fed on the test diets for 60 days. The results demonstrated that AgNPs reduced growth performance and enhanced the feed conversion ratio dose-dependently. Supplementing 0.75 g kg-1 curcumin at a low AgNP level improved the growth rate, while its inclusion at a high AgNP level led to further suppression of growth performance. The highest hematocrit value, hemoglobin concentration and white blood cell count were recorded in the group receiving 0.75 g kg-1 curcumin. Serum glucose, cholesterol and triglyceride concentrations were elevated by increasing AgNP levels. However, curcumin inclusion, particularly at the lower level of AgNPs significantly decreased their values. Similarly, intestinal alkaline protease and lipase activities were progressively reduced by increasing dietary AgNP contents, but, significant improvements were observed by curcumin application at the lower AgNP level. Our results revealed that curcumin supplementation could limit the toxic effects of lower dietary AgNP contents.

Effect of dietary antioxidant supplements (selenium forms, alpha-tocopherol, and coenzyme Q10) on growth performance, immunity, and physiological responses in rainbow trout (Oncorhynchus mykiss) using orthogonal array design.

Dietary supplements containing antioxidants play an important role in reducing the risk of peroxidative attack in aquatic animals. In this work, an orthogonal array design (L9: 34) was used to evaluate the effect of four dietary antioxidant supplements on the physiological responses of rainbow trout at three levels. The supplements included different (A) selenium (Se) forms (inorganic, organic, and nanoparticle), (B) Se content (0, 0.3, & 0.5 mg/kg feed), (C) vitamin E (VE) content (0, 100, & 150 mg/kg feed), and (D) coenzyme Q10 (CoQ10) content (0, 10, & 20 mg/kg feed). Fish with an average body weight of 8.35 ± 0.33 g were randomly allocated to different experimental groups. According to the results, the antioxidant supplements included in the diet had no significant effects on the growth performance of fish (P > 0.05). Immunological and antioxidant parameters were mainly improved by the Se form (Nano-Se) and dietary CoQ10 supplementation. In addition, Se form and VE were more effective in digestive enzyme activities and hematology indices in comparison to other dietary antioxidants. Additionally, diets supplemented with nano-Se along with CoQ10 and VE improved fish resistance/stamina against stress. In conclusion, a more effective combination of the four antioxidant supplements was A2/3B2/3C3D3 (i.e., 0.5 mg/kg organic/nano-Se, 150 mg/kg VE, and 20 mg/kg CoQ10), which could mainly improve the physiological responses of rainbow trout.

Biological Impact of Photoperiod on Fairy Shrimp (Branchinecta orientalis): Life History and Biochemical Composition.

B. orientalis, fairy shrimp, is often among the most conspicuous invertebrates inhabiting temporary aquatic habitats with a typical variation in environmental conditions. Its life history characteristics and biochemical composition were studied under four different photoperiodic regimes (24L:0D, 0L:24D, 16L:8D, and 12L:12D). The significantly highest cumulative and initial hatching rates (48 h) were obtained at 24L:0D (p < 0.05). Cultivating the larvae under different photoperiods did not significantly affect specific growth rate (SGR) (p > 0.05). However, higher final total body length and daily growth rate were recorded under constant darkness. Higher lipid content was found at 24L:0D to the extent that it was more than two times higher than that at 16L:8D and 12L:12D (p < 0.05). There was also a remarkable increase in body crude protein content at 24L:0D (p < 0.05). Body fatty-acid profiles of the fairy shrimps were also affected by culture condition (p < 0.05). Extension of lighting period resulted in a subtle increase in body contents of arginine, lysine, histidine, isoleucine, leucine, valine, methionine, and phenylalanine, especially in the group kept under a 16L:8D regime. The highest and lowest digestive enzyme activity was observed at 0L:24D and 24L:0D, respectively (p < 0.05). In contrast, the highest and lowest soluble protein content was recorded at 24L:0D and 0L:24D, respectively (p < 0.05). Similarly, antioxidant status was significantly higher at 0L:24D (p < 0.05). In conclusion, a 16L:8D light-dark cycle might be an optimal condition in terms of growth performance and physio-biochemical characteristics. These findings could be helpful in optimizing the rearing conditions for upscaling B. orientalis production.

Comparative study of host-associated and commercial probiotic effects on serum and mucosal immune parameters, intestinal microbiota, digestive enzymes activity and growth performance of roach (Rutilus rutilus caspicus) fingerlings.

The study aimed to isolate host-associated probiotic (HAP) lactic acid bacteria from intestine of adult Caspian roach and compare the efficacy of HAP with a commercially available probiotic strain (Pediococcus acidilactici) on the growth and feed utilisation, digestive enzymes and systemic and mucosal immune system of roach fingerling. The HAP strain isolated from roach intestine was Enterococcus faecium strain CGMCC1.2136. The experiment was a simple completely randomized design and lasted for eight weeks. Two hundred and seventy fish with an average weight of 12 g randomly distributed into nine tanks. The trial consisted of three treatments with three respective replications. During the experimental period, fish received basal diet without any bacterial supplementation (as the control group), basal diet enriched with 108 CFU g-1 HAP or 107 CFU g-1 CP. At the end of the experiment, serum immune parameters of those fish fed HAP including alkaline phosphatase activity, total protein content, total immunoglobulin level, lysozyme activity and complement activity (ACH50) were significantly higher that other experimental groups (P < 0.05). Similarly, dietary supplementation of HAP resulted in better mucosal immune parameters in comparison to control group and commercial probiotic administration (P < 0.05). Intestinal heterotrophic bacteria and autochthonous LAB counts of those fish fed HAP were significantly higher than other experimental groups at the end of the experiment as well as 15 days seizing probiotic administrations (P < 0.05). Fish fed with HAP containing diet presented significantly higher amylase, lipase and protease activity in comparison to the CP fed fish and the control group (P < 0.05). Growth indices of those fish fed HAP were significantly higher than other treatments (P < 0.05). The highest carcass protein and ash content along with the lowest body moisture content belonged to those fish received HAP (P < 0.05). In conclusion, the use host-HAP resulted in better immune competence and growth performance and it seems aquaculture sector should probably focus on the development of probiotics isolated from the cultured species instead of using terrestrial probiotics with greatly different requirements and environmental conditions.