Effect of Dietary Carbohydrate‐to‐Lipid Ratio on Growth and Carcass Composition of Juvenile Abalone, Haliotis discus, Reeve 1846

Abstract

The optimal dietary carbohydrate (C) : lipid (L) ratio on growth and carcass composition of juvenile abalone, Haliotis discus, was determined. A total of 1260 juveniles were randomly distributed into 18 containers. Six experimental diets containing different ratios of C to L (49:1, 48:2, 47:3, 45:5, 43:7, and 41:9) were prepared and referred to as the C49:L1, C48:L2, C47:L3, C45:L5, C43:L7, and C41:L9 diets, respectively. Water stability of the experimental diets was measured 12, 24, and 48 h after seawater immersion. Crude protein, L and ash content of the experimental diets decreased with time. Survival of abalone fed the C48:L2 diet was higher than that of abalone fed the C49:L1 and C41:L9 diets. Weight gain and specific growth rate (SGR) of abalone fed the C49:L1, C48:L2, and C47:L3 diets were higher than that of abalone fed the C45:L5, C43:L7, and C41:L9 diets. Crude L content of the soft body of abalone was directly reflected from dietary crude L content. In conclusion, the optimal dietary C : L ratio was estimated to be 48:2 and 47:3 based on survival, weight gain, and SGR of juvenile abalone, respectively. Greater than 3% L content in the diet deteriorated performance of this species of abalone.

The role of aquafeeds in abalone nutrition and health: A comprehensive review

“…However, it is generally considered that 5% is the maximum inclusion for abalone aquafeeds (Uki, Kemuyama, & Watanabe, 1985). Higher levels of lipids deteriorate the growth of certain species, such as H. discus (Lee et al, 2019) and Haliotis asinina (Bautista-Teruel et al, 2011). As Durazo-Beltrán, D'Abramo, Toro-Vazquez, Vasquez-Peláez, and Viana (2003) reported, H. fulgens grew best when diets contained 1.5% lipid, H. asinine grew best at a maximum of 6.1% (Bautista-Teruel et al, 2011) and H. midae at a maximum of 7% (Green, Jones, & Britz, 2011).…”

“…Lipids, as with other macronutrients, are essential due to their role in reparation and generation of new tissues in aquatic animals (Lee et al, 2019). The most used lipid sources in abalone aquafeeds are single sources or a combination of fish oil, soybean oil, and cod liver oil.…”

“…Indeed, carbohydrates are mainly used for locomotion and respiration (Fleming et al, 1996), while proteins are prioritized for tissue building and maintenance, and lipids are utilized for cell membrane formation and gonad maturation (Dunstan et al, 1996; Uki, Sugiura, & Watanabe, 1986). When carbohydrate intake is restricted or abalone is under stress, they use protein as an alternative energy source (Lee et al, 2019). Carbohydrates are broken down into acetyl CoA or Coenzyme A, which are subsequently used as a substrate for the tricarboxylic acid cycle or opine, lactate and oxaloacetate derivatives.…”

“…Macronutrients are usually included in high quantities in aquafeeds, which makes it possible for abalone to consume the carbohydrates and lipids for energy production. This leaves all the existing protein to be used for building muscle via the “protein‐spare effect” (Lee et al, 2019). The right percentage of protein in formulated feeds is the amount that increases the current growth rate of 2–3 cm per year (achieved with natural seaweed), reducing the on‐farm rearing period to less than 5 years (Hahn, 1989).…”

“…Higher levels of lipids deteriorate the growth of certain species, such as H . discus (Lee et al, 2019) and Haliotis asinina (Bautista‐Teruel et al, 2011). As Durazo‐Beltrán, D'Abramo, Toro‐Vazquez, Vasquez‐Peláez, and Viana (2003) reported, H .…”