A comparative analysis of the effect of low-cost fish and commercially compounded feed on growth performance and organoleptic quality of hybrid grouper (Epinephelus fuscoguttatus × Epinephelus lanceolatus) in cage farming in Kuala Penyu, Sabah, and nutritional costs

A 25-week feeding trial was conducted to assess the growth performance, organoleptic quality, and to estimate the viability of nourishing hybrid grouper (Epinephelus fuscoguttatus x Epinephelus lanceolatus) with low-cost fish (LCF) and commercially compound feed (CCF). A group of 3600 juvenile fish (182g) were released in four sea cages and fed with either LCF or CCF in duplicate. At the end of the trial, the hybrid grouper provided LCF attained a significantly higher (P<0.05) final body weight (971.00±24.04g) than those fed with CCF (838.50±17.68g). While the estimated feed cost of hybrid grouper fed with LCF (RM7.84 ± 0.45) was lower than those fed with CCF (RM9.28 ± 0.37), no significant difference was found in the fish survival and there was no clear bias in consumer preferences for either fish fed with LCF or CCF (P>0.05). Although technicalities of fish fed with LCF suggest that LCF is more efficient than CCF, feeding LCF to high-value fish is an unsustainable practice as LCF is usually obtained through trawling – a destructive fishing method for the marine ecosystem. Therefore, feeding with CCF without the use of LCF as the source of protein for its fishmeal will contribute to sustainable aquaculture. In order to convince the local farmers in Sabah to adopt the practice of feeding CCF, future research should focus on completing the species-specific diet formulation to promote optimum growth, and find ways to reduce the CCF local selling price.

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Supplementing Chitosan Oligosaccharide Positively Affects Hybrid Grouper (Epinephelus fuscoguttatus ♀ × E. lanceolatus ♂) Fed Dietary Fish Meal Replacement With Cottonseed Protein Concentrate: Effects on Growth, Gut Microbiota, Antioxidant Function and Immune Response

Frontiers in Marine Science ◽

10.3389/fmars.2021.707627 ◽

2021 ◽

Vol 8 ◽

Author(s):

Guofeng Chen ◽

Bin Yin ◽

Hongyu Liu ◽

Beiping Tan ◽

Xiaohui Dong ◽

...

Keyword(s):

Growth Performance ◽

Fish Meal ◽

Biological Activities ◽

Challenge Test ◽

Serum Glucose ◽

Chitosan Oligosaccharide ◽

Cottonseed Protein ◽

Hybrid Grouper ◽

Significant Difference ◽

Epinephelus Fuscoguttatus

Oligosaccharides have recently received much attention from researchers owing to their multiple biological activities. This study was conducted to investigate the effects of a diet with reduced fish meal and chitosan oligosaccharide (COS) supplementation on a hybrid grouper (Epinephelus fuscoguttatus ♀ × E. lanceolatus ♂). Seven isonitrogenous and isolipidic types of diet were formulated to feed the groupers for 56 days. To prepare the feed, a reference diet (FM group) containing 55% fish meal was used. Concentrated cottonseed protein (CPC) was used to replace 45% of the fish meal protein, and different COS supplementation levels (0, 0.2%, 0.4, 0.6, 0.8, and 1%) were added. After an 8-week breeding trial, Vibrio harveyi bacteria were injected into the groupers for a 7-day challenge test. The results showed that the FM and COS0.4 groups showed the best growth performance among the groups (p < 0.05); however, there was no significant difference in the survival rate (p > 0.05). Unlike in the FM group, adhesion and breakage of the intestinal plica occurred in the COS0 group. The height and width of the gut fold reached maximum values in the COS0.4 group (p < 0.05). Microbiome sequencing suggested that there was a stable microbiota core in the gut of the groupers. With increasing COS levels, the abundance of both beneficial bacteria and conditional pathogens increased; the activities of serum glucose oxidase, catalase, and total superoxide dismutase also increased (p < 0.05). In the gut tissue, the activities of glutathione peroxidase, glutathione reductase, and glutamine increased first but then decreased (p < 0.05); the contents of lysozyme, acid phosphatase, complements C3 and C4, and IgM showed upward trends (p < 0.05). Compared with that in the FM group, the expression of IL-1β and TNF-α in the COS0 group was upregulated. Gene expression levels of TLR22, TGF-β, and Nrf2 increased first but then decreased with COS supplementation levels (p < 0.05). COS supplementation reduced the cumulative mortality of the groupers in the challenge test (p < 0.05). In general, the results of this study demonstrated that dietary COS supplementation enhanced growth performance, intestinal health, and antioxidant and immune responses of groupers fed with a low-fish meal diet. The optimal and acceptable levels of COS supplement were 0.45 and 0.4–0.6%, respectively; these values can provide a reference for developing aquatic prebiotics.

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