Optimum protein-to-lipid ratio requirement of the juvenile shi drum (Umbrina cirrosa) as estimated by nutritional and histological parameters

Abstract

The shi drum, Umbrina cirrosa, is considered quite promising candidate and emerging alternative Mediterranean aquaculture species to the dominant, European seabass, Dicentrarchus labrax, and gilthead seabream, Sparus aurata, due to its high growth rate and feed efficiency (Segato, Corato, Fasolato, & Andrighetto, 2005). Shi drum feeds mainly on invertebrates and fish (Abellan & Basurco, ), suggesting that this species has high protein requirements. Moreover, the shi drum has a good adaptation capacity to culture conditions and, unlike the winter reproducers seabass and seabream, it is a spring-summer reproducer (Mylonas et al., 2004), thus providing a good species to grow in parallel with the existing cultivated species. Shi drum is a demersal fish, member of the Sciaenidae family (Nelson, Grande, & Wilson, 2016), living on the sandy bottom of maximum 100 m depth, and is distributed all around the Mediterranean Sea area, including the Black Sea. The size of the shi drum during catch is usually around 50-60 cm, but it can reach up to 1 m length and 12 kg weight (Mylonas et al., 2000a). In aquaculture settings, this species can achieve a weight of 500 g in only 15 months, which is near twice the growth rate of seabass and seabream (Fabi & Fiorentini, 1993; Mylonas et al., 2000b), thus making the shi drum a very attractive species for aquaculture. AbstractThe shi drum is an emerging Mediterranean aquaculture species that has gained increasing interest in recent years. However, the nutrient requirements of this species remain to be determined to optimize its culture. The present study evaluated the effects of dietary protein (470g/kg or 520g/kg) to lipid ratios (100g/kg, 150 or 200g/ kg) on the growth performance, nutrient utilization and tissue morphology of the shi drum (7 g average initial weight). Dietary protein levels positively correlated with weight gain, showing high protein demands (>470g/kg) for this species. Nonetheless, dietary lipid levels negatively affected growth rate, feed intake and efficiency, and protein utilization, suggesting that this macronutrient cannot be efficiently utilized in high concentrations (>100g/kg). Histological evaluation revealed fat accumulation within the hepatocytes and the enterocytes with increasing dietary lipid levels, starting from 150g/kg lipid inclusion. Overall, our results confirm the high dietary protein requirements of the shi drum (>470g/kg for fish of 7 g initial weight) and suggest that lipid levels should not exceed 100g/kg of inclusion in the diets as this species has a low tolerance to this macronutrient. K E Y W O R D Sdiversification, emerging aquaculture species, feed utilization, growth performance, histological score, nutrient requirements | 445 KOKOU et al.

Comparison of Artificial Feed and Natural Food by the Growth and Blood Biochemistry in Chinese Sturgeon Acipenser sinensis

“…We speculate that there are significant differences in the nutritional requirements of Chinese sturgeon at different ages. Nutritional composition and ratio of diets play important roles in fish growth [28][29][30]. As the scale of artificial conservation of Chinese sturgeon continues to expand, quantity and quality of natural feed cannot be guaranteed, and an artificially formulated diet must be used.…”

Effects of Dietary Protein-to-Energy Ratios on Growth, Immune Response, Antioxidative Capacity, Liver and Intestinal Histology, and Growth-Related Gene Expression in Hybrid Yellow Catfish (Pelteobagrus fulvidraco ♀ × Pelteobagrus vachelli ♂ )

“…The results show a considerable improvement in villus height and width in P/E95 based on gut morphometry. The histomorphometry analysis of a recent work by Kokou et al [ 29 ] showed that the dietary protein-to-energy ratio affected intestinal health and ameliorated villus heights in juvenile shi drum. The ability of hybrid yellow catfish to digest their diets more effectively seems to be positively influenced by optimal dietary P/E ratios, improving their health, growth potential, and productivity.…”

“…Lipid is deposited in vacuoles, which results in steatosis primarily in the liver, but it can also build up in enterocytes, as dietary lipid levels surpass the oxidation capability. There is evidence to support these effects on a wide variety of fish species, including juvenile shi drum ( Umbrina cirrosa ) and meagre ( Argyrosomus regius ) [ 29 , 30 ]. Hence, finding an ideal dietary protein-to-energy ratio is so essential to a fish's health and physiological condition.…”

“…Proper protein-toenergy ratios in diets have the potential to negatively impact intestinal morphology, which affects nutrient absorption and digestion, as well as liver function and morphology. These effects may depress the immune system and raise the risk of infectious diseases [26][27][28][29]. Lipid is deposited in vacuoles, which results in steatosis primarily in the liver, but it can also build up in enterocytes, as dietary lipid levels surpass the oxidation capability.…”

Combined effects of dietary starch:Protein ratios and short cycles of fasting/refeeding on Nile tilapia growth and liver health

“…Hepatic steatosis is common in fish fed with diets comprising high lipid (Kokou et al., 2019) or carbohydrates levels (Fernandes Junior et al., 2016), due to increased lipid deposition in the liver. Xie et al.…”