EFFECTS OF DIETARY COMMERCIAL YEAST GLUCAN ON INNATE IMMUNE RESPONSE, HEMATOLOGICAL PARAMETERS, INTESTINAL MICROBIOTA AND GROWTH PERFORMANCE OF WHITE FISH (Rutilus frisii kutum) FRY

Abstract

This study investigates the effects of different levels of commercial yeast glucan (CYG) on innate immune response, hematological parameters, intestinal microbiota, growth performance and survival rate of white fish (kutum) fry. Specimens (1.1 ± 0.15 g) were randomly allocated into 15 tanks (100 L) at a density of 25 fish per tank and triplicate groups were fed either a basal control diet (0% CYG) or a basal diet supplemented with yeast (0.5, 1, 1.5 or 2% CYG) for 60 days. All dietary CYG levels significantly increased the innate immune responses (IgM levels and lysozyme activity) (P < 0.05) and the highest survival was observed in the 1 and 1.5% CYG group. Compared to the control group, CYG had no effects on RBC, Hct and Hb (P > 0.05), but WBC levels were significantly higher in CYG fed fish (P < 0.05). Microbiological assessment indicated that the viable culturable autochthonous and lactic acid bacteria (LAB) levels significantly elevated in 0.5 and 1% treatments. Our results indicated that low levels of dietary CYG (0.5 and 1 %) improved growth performance, body protein levels and survival rate compared to the control treatment (P < 0.05). These results indicate that CYG stimulates innate immune response, improves growth performance and modulates intestinal microbiota of kutum fry. Thus, we suggest that low level CYG may be used as a beneficial dietary supplement in kutum fry culture.

Recovery from Hypersaline-Stress-Induced Immunity Damage and Intestinal-Microbiota Changes through Dietary β-glucan Supplementation in Nile tilapia (Oreochromis niloticus)

“…β-glucan supplementation could significantly decrease HCT, RDW, PLT, and PCT in O. niloticus in brackish water. However, this result is at odds with previous studies where β-glucan increased WBC and RBC in Trachinotus ovatus [49], Rutilus Frisii kutum [19], and Labeo rohita [50]. It seems that the response of hematological indicators in fish fed β-glucan supplements depends on the condition of environmental stress.…”

“…Intestinal bacterial metabolism in aquatic animals shows important functions in health regulation and nutrient absorption [16]. Dietary β-glucan supplementation can improve intestinal microbiota communities in Cyprinus carpio [17], Scophthalmus maximus [18], Rutilus Frisii kutum [19], and Cyprinus carpio L [20]. β-glucans can also increase the dominance of the intestinal microbiota richness in L. vannamei under the conditions of ammonia and low-salinity stress [12,21].…”

Mannanoligosaccharides as a Carbon Source in Biofloc Boost Dietary Plant Protein and Water Quality, Growth, Immunity and Aeromonas hydrophila Resistance in Nile Tilapia (Oreochromis niloticus)

“…Bacillus subtilis bacteria have β-mannanase enzymes that can hydrolyze mannan oligosaccharides and use them for its proliferation [ 16 ] and production of their metabolites, which are mainly lactic acid and acetic acid [ 17 ]. The proliferation of lactic acid bacteria in water or the intestine suppresses the colonization of Gram-negative pathogenic bacteria [ 18 ]; moreover, pathogenic bacteria proliferation can be eliminated by MOS itself, as it is capable of attaching to glycoprotein receptors of pathogens, preventing their attachment and colonization [ 19 ]. The combination of both MOS and lactic acid bacteria may have a beneficial effect on fish by promoting performance, immunity and disease resistance [ 20 ].…”

Efficiency of β-glucan utilisation in fish culture

“…Nhiều nghiên cứu cho thấy việc bổ sung βglucan có tác dụng thúc đẩy tốc độ tăng trưởng của nhiều loài cá như ở cá chim vây ngắn Trachinotus ovatus cho ăn bổ sung BG cho tốc độ sinh trưởng cao hơn hẳn so với cá nghiệm thức đối chứng [8,12]. Kết quả đẩy mạnh tốc độ sinh trưởng cá nuôi cũng tương tự trên các loài khác như cá đù vàng, Pseudosciaena crocea [13], cá lóc, Channa striata [14], cá hồi Đại Tây Dương, Salmo salar [15], cá chép koi, Cyprinus carpio koi [16], cá rohu, Labeo rohita [17], white fish, Rutilus frisii kutum [18]. Tuy nhiên, một vài nghiên cứu cho thấy β-glucan không có tác dụng lên sinh trưởng của cá như đối với cá rô phi, Oreochromis niloticus [19], cá chẽm sọc lai, Morone chrysops x Morone saxatilis [20].…”

“…Việc ảnh hưởng của việc bổ sung prebiotic lên thành phần sinh hóa của cá vẫn chưa được hiểu biết một cách đầy đủ và có thể tùy thuộc vào từng loài, hoặc chịu ảnh hưởng của từng loại prebiotic. Cá white fish, Rutilus frisii kutum cho ăn bổ sung BG làm tăng hàm lượng protein, tuy nhiên hàm lượng lipid, tro và độ ẩm không thay đổi[18]. Ở cá chim vây ngắn, việc bổ sung lượng β-glucan thích hợp và thức ăn đã cho kết quả tăng hàm lượng protein và giảm hàm lượng lipid trong cơ của cá[12].…”