THE EFFECT OF CRYSTALLINE AMINO ACIDS SUPPLEMENTATION IN THE REDUCED INTACT PROTEIN DIETS ON MUSCLE GROWTH AND INTESTINAL MORPHOLOGY OF CHANNEL CATFISH Ictalurus punctatus

1,2 Shimaa M. Salem*, 3,4 Iman Ibrahim, 3 Attila Karsi, 2 Hisham A. Abdelrahman and 2 D. Allen Davis
 
¹ Department of Nutrition & Nutritional Deficiency Diseases, Faculty of Veterinary Medicine,  Mansoura University, 35516 Egypt
 2School of Fisheries, Aquaculture and Aquatic Sciences, Auburn University, Auburn, AL  36849, USA. davisda@auburn.edu
3Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, Starkville, MS, USA.
4 Department of Pathology, Faculty of Veterinary Medicine, Mansoura University, 35516 Egypt
 

Muscle growth is the main indication of fish growth and affected by nutrition. Particularly, fish require dietary protein and amino acids to support muscles, tissues and organs growth. This  study was aimed to assess the effect of indispensable (IAAs/EAAs) and dispensable amino acids (DAAs/NEAAs) supplementation with the reduction of dietary intact protein (IP) content in channel catfish Ictalurus punctatus diets and their effect on muscle growth, intestinal morphology and other fish health indicators.

9 isolipid (8%) experimental diets were formulated with different crude protein levels)  32 basal, 30, 28, 26, 24 % IP)  with supplementation of Essential amino acids (EAAs) ; Lysine and Histidine  to meet EAAs/IAAs requirements for channel catfish Ictalurus punctatus according to NRC 2011 with and without addition of  Nonessential amino acids (NEAAs); Glutamic  acid and Glycine to the low protein diet (24%IP) at different rate(2, 4, 6, 8% NEAAs) . Experimental fish (average initial weight 10.56± 0.1g) were randomly allocated into 9 groups, 4 replicate per each 15 fish/ tank in indoor recirculating system and fed experimental diets two times/day according to % of body weight and weighted bi-weekly. Dissolved oxygen, temperature and salinity were measured 2times/day while, water samples were collected 2 times/week for measuring of Total ammonia nitrogen, Nitrite and pH.

At the end of the experiment, 4 fish per tank were randomly chosen then anesthetized for collecting serum samples for oxidative stress and immune assay. Then, Samples from dorsal muscle and intestine were collected and kept in 10% buffered formalin for measuring the skeletal muscle fibers diameter and numbers. Also, the intestinal fold, enterocyte and microvillus height were measured.

The growth results showed that, there is no significant difference (P>0.05) in the final means (g), total weight gain(g) and feed conversion ratio (FCR) among fish groups which fed with {32 (control), 30, 28 & 26% CP supplemented with EAAs Lysine and Histidine}. However, fish fed with 24 % CP supplemented with EAAs showed statistically different (P<0.05) compared to 32 and 30% CP diets. While the NEAAs supplementation to 24% CP diet with EAAs did not show an obvious contribution in catfish growth response. Histological analysis still ongoing and data will be presented in the conference.