Sherif

Evaluation of Some Probiotics on Growth Performance and Immunity Status of Nile Tilapia.

Sherif, A. H., 1 Saker, O. A.2 and El-Sharawy, M. E.3

1- Department of fish disease, Animal health research institute. Kafr El- Sheikh provincial lab, agriculture research center.

2- Department of biochemistry, Animal health research institute. Kafr El- Sheikh

3- Department of animal production, Faculty of agriculture, Kafrelsheikh University.

Abstract

Growing concern for the high consumption of antibiotics in aquaculture has initiated a search for alternative methods of disease control by improving resistance against infectious disease which can be achieved by using of probiotics. The objective of the present study was to evaluate the influence

Adverse environmental situations may acutely or chronically affect the health of fish, altering some of their biochemical parameters and suppressing their innate and adaptive immune responses (Giron-perez et al., 2007). Antibiotics have been used for long time as growth promoting agents but adversely affected growth and food conversion as well as multiple of drug resistant bacteria and antibiotic residues in fish meat (Wary and Davies, 2000). Therefore, using of natural feed additives to substitute antibiotic had become great interest (Kumar et al., 2003). Probiotics are defined as microbial dietary addetives that beneficially affect the host physiology by modulation immunity system, as well as improving nutritional and microbial balance in the intestinal tract (Villamil et al., 2002). Using of some kind of probiotics in aquaculture water regulated the microflora of aquaculture water, controlled pathogenic microorganisms, enhanced decomposition of the undesirable organic substances in aquaculture water, and improved ecological environment of aquaculture. In addition, the use of probiotics can increase the population of food organisms, improve the nutrition level of aquaculture animals and improve immunity of cultured animals to pathogenic microorganisms (Patterson and Burkholder

Differential leukocytic count was calculated according to Schalm (1986). Mean Corpuscular Volume hemoglobin concentration were calculated according to the formula mentioned by Dacie and lewis (1975). Red blood cell (RBCs) and White blood cell (WBCs) counts were counted by haemocytometer according to Stoskopf (1993). In addition to MCV Mean Corpuscular Volume, MCH Mean Corpuscular Volume hemoglobin and MCHC Mean Corpuscular Volume hemoglobin concentration were calculated according to the formula mentioned by Dacie and lewis (1975).

MCV = PCV x 10 / RBCs as m/mm3.

MCH =HB contentgm/100ml x 10/ RBCs as m/mm3.

MCHC =HB contentgm/100ml x100 / PCV.

The concentration of total protein weichsellbaum (1946) and albumin (Doumas et al., 1971) were measured by colorimetric methods, While, globulin concentrations were determined by subtracting the concentration of total protein from albumin concentration. The activity of the liver enzymes, Aspartate amino transaminase (AST) and Alanine amino transaminase (ALT) was determined according to (Reitman and Frankel, 1957).

Challenge test: After 90 days of feeding, a total number of 0 fish (10 fish from each treatment) were injected I/P with the pathogenic A. hydrophila (0.3 ml of 108cells/ml), the injected fishes were kept under observation for 14 day to record the mortality rate.

Mortality rate % = No. of death in specific period x