Browsing by Author "Hunter, Amy"

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    The effects of probiotics on the physiological and biochemical development of the digestive tract of commercially raised dusky kob (Argyrosomus japonicus) larvae
    (Stellenbosch : Stellenbosch University, 2015-04) Hunter, Amy; Pieterse, Elsje; Brink, Danie; Stellenbosch University. Faculty of Agrisciences. Dept. of Animal Sciences.
    ENGLISH ABSTRACT: Aquaculture is one of the fastest growing food producing sectors in the world. Over the past few years, aquaculture research has focused on improving rearing protocols and standards for the culture of aquatic organisms. Probiotics are gaining increasing interest as an alternative to antibiotics to improve animal health and welfare. The effects of probiotics on the physiological and biochemical development of the digestive tract of commercially raised Argyrosomus japonicus (dusky kob) larvae were investigated. Two probiotic treatments were compared to a control where the standard rearing protocol was applied. The growth of the larvae and histological development of the digestive tract was studied. The specific enzyme activity of key digestive enzymes was determined. Amylase, trypsin, pepsin, alkaline phosphatase, aminopeptidase N and leucine-alanine peptidase were assayed. The mean growth of the control group of larvae differs from the CSIR and BactoSafe treatment groups (P = <0.001). There were no differences in the histological development between the control and two treatments. The histology did indicate a slight delay in development of the digestive tract when compared to previous studies on dusky kob. No significant differences were observed between the control and treatment groups for any of the enzyme assays. The effect of probiotics on the development of the digestive system of dusky kob larvae could not be definitively described as it was not determined to what extent the probiotics had established in the gut. What the study did conclude was that the enzyme assays need to be refined in order to determine the optimal reaction conditions required for the determination of specific enzyme activity in commercially raised dusky kob.