The effect of weaning diet type on grey mullet (Mugil cephalus) juvenile performance during the trophic shift from carnivory to omnivory

• Published in: Aquaculture 2020-03, Vol.518, p.734848, Article 734848
• Main Authors: Koven, W., Gisbert, E., Meiri-Ashkenazi, I., Nixon, O., Israeli, D., Tandler, A., Nolasco Soria, H., Solovyev, M.M., Rosenfeld, H.
• Format: Article
• Language: English
• Subjects: Amylase; Grey mullet; Intestinal maturation index; Omnivore; Weaning diet
• ISSN: 0044-8486; 1873-5622
• DOI: 10.1016/j.aquaculture.2019.734848

In captive grey mullet (Mugil cephalus) juveniles, the weaning stage overlaps the period where there are changes in the ontogeny of digestive enzymes as the fry transit from carnivory to omnivory. The aim of this study was to evaluate growth, survival, weight distribution and the activity of pancreatic and brush border digestive enzymes when fry are fed a carnivorous, herbivorous or omnivorous weaning diet. Fifteen 17-L aquaria in a flow through system with 40‰, UV treated, temperature (24.5 ± 0.5 °C) controlled seawater were stocked with eighty-five 23 dph grey mullet larvae per aquarium. This allowed the testing of three weaning dietary treatments, differing in their protein and carbohydrate content, in 5 replicate aquaria per treatment from 24 to 53 dph. Diet 1 was the dried macroalgal species Ulva lactuca and was designated as a low protein: high carbohydrate herbivorous diet. Diet 2 was a commercial microencapsulated starter feed designated as a high protein: low carbohydrate carnivorous diet. Diet 3 was a 1:1 ww mixture of diets 1 and diet 2 representing an omnivorous feeding regime. The average final weight of the omnivorous feeding fish was significantly (P