Effects of Discontinuous Administration of Dietary Mannan oligosaccharide and β-1,3-glucan on Hematological and Blood Serum Biochemical Parameters of Rainbow trout (Oncorhynchus mykiss)

• Main Authors: Reza Akrami, Fatemeh Nouri, Amir Hossein Naseri, Majid Razeghi Mansour
• Format: Article
• Language: fas
• Published: Ferdowsi University of Mashhad 2016-04-01
• Series: پژوهشهای علوم دامی ایران
• Subjects: Blood variables; Prebiotic; Rainbow trout (Oncorhynchus mykiss)
• Online Access: http://ijasr.um.ac.ir/index.php/animal/article/view/38692

Introduction Bans and restrictions of antibiotics as feed additives in fish culture in many countries have resulted in the increase in studies on alternative dietary supplements such as prebiotics to enhance the health and production of cultured fish. Prebiotics are nondigestible food ingredients that beneficially affect the host by selectively stimulating the growth and/or activity of one or a limited number of bacteria in the colon. In addition, prebiotics promote the growth of lactic acid bacteria that are beneficial to health and lessen the density of pathogenic microorganisms. Because of the conservation of immune system, it is suggested that alternate administration of different immunostimulants may activate different parts of immune system of shrimps and take advantage of different immunostimulants to solve the problem of immunity fatigue and enhance the immunity continuously. However, there is no report on the discontinuous administration of immunostimulants for rainbow trout. Thus, considering the strategic importance of this species, the goal of this study was to assess the effects of discontinuous administration of dietary mannan oligosaccharide and β-1,3-glucan on hematological and blood serum biochemical parameters of rainbow trout. Materials and Methods A 6-week trial was conducted to compare the effects of discontinuous administration of dietary mannan oligosaccharide and β-1,3-glucan on hematological and blood serum biochemical parameters of rainbow trout (Oncorhynchus mykiss). Four feeding strategies were set, including feeding prebiotic-free diet continuously (control), feeding dietary prebiotic continuously (1.5 g kg-1), feeding dietary alternately (one week prebiotic+one week control diet and 2 Day prebiotic+5 Day control diet). Juveniles were fed the experimental diet in rate of 4% of the body weight per day, spread across two feeding time. At the end of the experiment, three fish were sampled randomly from each tank and were anesthetized with clove solution, and blood was drawn from the caudal vein, using a syringe. Then, blood samples were introduced to both heparinized and non-heparinized tubes in order to perform haematological and biochemical studies, respectively. Blood sera were obtained by centrifuging blood samples at 3000 rpm for 5 min, and the sera were removed with a disposable transfer pipette and stored at -20ºC until analysis for biochemical and hematological studies. The determined Parameters were the number of red blood cells (RBC), white blood cells (WBC), hematocrit (PCV), and hemoglobin (Hb). Differential white blood cell counts, including neutrophiles (heterophiles), lymphocytes and monocytes were also identified. Statistical analysis was carried out using one-way analysis of variance using SPSS. Differences between means were determined using Duncan’s multiple test (P