Growth Response of Nile Tilapia Oreochromis niloticus to Dietary L‐Ascorbic Acid, L‐Ascorbyl‐2‐Sulfate, and L‐Ascorbyl‐2‐Polyphosphate

Abstract

Abstract.— Purified diets were formulated and fed to seven groups of Nile tilapia Oreochromis niloricus fingerlings for 12 weeks. Six of the formulated diets contained 5 or 50 mg/kg of ascorbic acid equivalent supplied either by L‐ascorbic acid (AA), L‐ascorbyl‐2‐sulfate (AS) or L‐ascorbyl‐2‐polyphosphate (APP). The seventh basal diet was ascorbate‐free and served as the control. The study indicated that APP or AS was more effectively utilized as a source of vitamin C than equimolar AA in promoting growth, improving food conversion, and preventing scurvy in Nile tilapia. Fish fed the ascorbate‐free diet and the diet containing 5 mg AA/kg exhibited external signs of scurvy at 10 weeks. Diets containing 5 mg/kg of ascorbic acid from AS or APP provided some growth with no overt signs of scurvy indicating that this concentration of AS and APP might be near the minimum requirements for the species. The best growth, food conversion ratio, survival rate, and ascorbic acid content in liver were obtained with the diet containing 50 mg ascorbate equivalent/kg diet from APP followed by the diet containing 50 mg ascorbate equivalent/kg diet from AS. Fish fed diets with 50 mg ascorbic acidkg diet from AS and APP gained 27.9% and 36.2% more weight, respectively, than fish fed diets with 50 mg ascorbic acidkg diet from AA. These results indicated nearly equal ascorbic acid activity from AS and APP.

Dietary ascorbic acid requirement for growth of striped catfish,Pangasianodon hypophthalmus(Sauvage, 1878) juveniles

“…Many of the farmed fishes, such as ictalurids, cichlids and cyprinids, cannot synthesize vitamin C de novo because they do not contain the enzyme, L‐gulono‐1,4‐lactone oxidase (Chatterjee, ; Dabrowski, ; Moreau, Dabrowski, & Sato, ; Xie, Niu, Zhang, & Bao, ; Yamamoto, Sato, & Ikeda, ). Ascorbic acid is soluble in water, and thus, leaching of this vitamin from feeds can be a serious issue (Abdelghany, ; Hilton, Cho, Brown, & Slinger, ; Hilton, Cho, & Slinger, ; Soliman, Jauncey, & Roberts, ). Wilson and Moreau () reported that AA is not stable in the native form as 50 mg/kg of the supplemental AA will be destroyed during the feed manufacturing process.…”

“…In L‐ascorbyl‐2 polyphosphate, the C‐2 carbon atom is esterified and highly reactive, which easily protects vitamin C from oxidation. Therefore, bioavailability of vitamin C is always found to be higher in L‐ascorbyl‐2 polyphosphate than any other vitamin C sources (Abdelghany, ). On account of these reasons, we used the L‐ascorbyl‐2 polyphosphate form of AA in our study.…”

Vitamin C requirement of adult genetically improved farmed tilapia, Oreochromis niloticus

“…Growth performance rates are correlated with metabolic rate, which are the primary factor regulating vitamin C requirement (Dabrowski 1991). Our results revealed that the dietary vitamin C requirement of adult GIFT (220-547 g) based on WG is *53.05 mg kg -1 , which is similar to juvenile tilapia (51 mg kg -1 ) with an initial body weight of 3.7 g (Nsonga et al 2009), Nile tilapia (50 mg kg -1 ) with an initial body weight of 0.56 g (Abdelghany 1996), but much higher than hybrid tilapia (15.98-18.22 mg kg -1 ) with an initial body weight of 1.53 g (Shiau and Hsu 1999). Although the stable forms of vitamin C were used in those experiments of larval and juvenile fish, the results about vitamin C requirements of tilapia were not unanimous.…”

“…Genetically improved farmed tilapia (GIFT) is an improved fish strain with excellent growth potential (Dey et al 2000). Many previous researches showed that nutrient requirements are primarily affected by the size of the fish and may vary among tilapia species (Abdel-Tawwab et al 2010;Al Hafedh 1999;Twibell and Brown 1998;Abdelghany 1996;Soliman et al 1994;Shiau and Lin 1993;Shiau and Shy 1998). There are several studies about the vitamin C requirements of tilapia, such as 15.98-18.82 mg kg -1 for hybrid tilapia (Shiau and Hsu 1999), 50 mg for Oreochromis niloticus (Abdelghany 1996), and 51 mg kg -1 for Oreochromis karongae (Nsonga et al 2009), but all of these studies have focused on the larval and juvenile stages of tilapia.…”

Development of Brood-stock Diets for Nile tilapia Under Hapa-in-Pond Hatchery System; Optimal Dietary Vitamin C Level for the Optimum Reproductive Performance and Fry Survival

“…Fecundity and embryo survival also increased in female rainbow trout with increased dietary Vitamin C levels [12]. As for Nile tilapia (Oreochromis niloricus), the detected requirement of dietary ascorbic acid for was 50 mg/kg for fingerlings [13], while, there was no much information considering the brood-stock requirement. On the other hand, previous levels of Vitamin C requirements were concluded under clear water conditions.…”