Effects of various diet formulations (experimental and commercial) on the morphology of the liver and intestine of rainbow trout (Oncorhynchus mykiss) juveniles

Abstract

The aim of the present study was to evaluate the effects of three formulated diets: wheat gluten proteinbased diets supplemented with Lys^Gly dipeptide (PP) or free lisine and glycine (AA), and a control diet without lysine supplementation (CON), two commercial starters: Aller Futura (AF), Aglo Norse (AN) and frozen Chironomidae larvae (CH) for on the growth and digestive system development of rainbow trout. The experiment lasted 28 days and survival at the end of the experiment was the highest in the group fed AF (87.9 AE 4.2%) and the lowest in the group fed the CON diet (74.0 AE 4.3%). Fish fed the CON diet showed a signi¢cantly lower crude protein content, and the AA group had a signi¢cantly higher lipid level (P 0.05) in body carcass compared with the other groups. The highest density of intestinal goblet cells (P 0.05) was observed in ¢sh fed the CON diet, while the lowest density was seen in the distal intestine in the AF group. The hepatocyte cytoplasm of all ¢sh stored more glycogen than lipids. These results indicate that wheat gluten protein-based diets supplemented with dipeptide Lys^Gly (PP) or free lysine and glycine (AA) supported growth, protein e⁄ciency rate and intestine epithelium homeostasis. On the other hand, ¢sh fed CON (lysine-de¢cient diet) showed lower survival and growth rate, and disturbances of intestine epithelium homeostasis, probably as a result of lysine de¢ciency.

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“…Lower numbers of PCNA-positive nuclei were observed in fish fed EFA-enriched Artemia, suggesting that the fatty acid profile of the provided live food was adequate to the feeding requirements of the larvae and thus did not lead to unnecessary, reparative hepatocyte proliferation (Ostaszewska et al, 2013).…”

“…PAS was also used as a control to stain glycogen with diastase (Gona, 1979). Antibodies directed against the proliferating cell nuclear antigen (PCNA) were applied to identify intestinal and hepatic cell proliferation (Ostaszewska et al, 2013). Apoptotic intestinal cells were detected immunohistochemically with a CPP-32 (caspase-3) rabbit polyclonal antibody .…”

“…Enzymatic secretion during ontogenesis was studied on various Acipenseridae (Żółtowska et al, 1999;NaporaRutkowski et al, 2009), but the physiological and morphological impact of different diets was not completely determined. However, free amino acids (FAA) and free fatty acids (FFA) are known to stimulate digestive processes and the assimilation of nutrients, and they also may have influence on digestive tract morphology, feeding behavior or food intake (Ostaszewska et al, 2008;Napora-Rutkowski et al, 2009;Naz and Türkmen, 2009;Ostaszewska et al, 2013).…”

“…In order to achieve higher survival, growth and stress-resistance numerous nutritional studies are conducted every year (Jalali et al, 2008;Ostaszewska et al, 2010;Ostaszewska et al, 2011;Noori et al, 2011).…”

Review on the use of insects in the diet of farmed fish: Past and future

“…Such deficiencies can primarily lead to an increase in feed intake (FI), because the fish will eat more to cover its basic needs, as exemplified with Lys . Subsequently, fish growth and the feed conversion rate may be affected (Ostaszewska et al, 2011) and deficiency symptoms may appear possibly followed by an increased sensitivity to diseases (Cowey, 1994;Helland and Grisdale-Helland, 2006;Kiron, 2012).…”