Effect of dietary L-malic acid supplementation on growth, feed utilization and digestive function of juvenile GIFT tilapiaOreochromis niloticus(Linnaeus, 1758)

Abstract

Summary Two feeding trials (FTs) were conducted in 2013 and 2014, respectively, to determine the optimal L‐malic acid (LMA) level for juvenile GIFT (Genetically Improved Farmed Tilapia) Oreochromis niloticus. Except for the LMA level, the FT1 and FT2 had a similar diet formulation. In FT1, LMA was included at 0 (basal diet), 1, 4, 8, 16 and 32 g kg−1, respectively. After 20 weeks, daily weight gain and feed conversion ratio were improved but not differentiated with 1–8 g kg−1 LMA. Further increasing the LMA supply initially decreased the feed intake (16 g kg−1), and then decreased both feed intake and feed utilization (32 g kg−1), thus impairing the fish growth. FT2 was subsequently conducted with a smaller LMA range (0, 0.5, 1, 2, 4 and 8 g kg−1, respectively) but was unfortunately terminated at the end of 8 weeks because 20% of the fish were badly injured during weighing. Unexpectedly, growth and feed utilization were still improved but not differentiated with 0.5–8 g kg−1 LMA. In FT2, beneficial effects of LMA inclusion on the digestive function (pepsin, foregut amylase and foregut lipase), the activities of serum lysozyme and hepatic superoxide dismutase, and liver lipid peroxidation (malondialdehyde concentration) were found. Taking the results of FT1 and FT2 together, it could be concluded that dietary LMA supplementation at low concentrations (0.5–8 g kg−1) could improve growth and feed utilization, but excess LMA (≥16 g kg−1) might compromise feed intake and/or feed utilization, thus impairing fish growth. To reduce feed costs in commercial practice, 0.5 g kg−1 LMA is recommended in the feed of juvenile GIFT tilapia based on the results of this study.

Dietary trans‐cinnamic acid application for rainbow trout (Oncorhynchus mykiss): II. Effect on antioxidant status, digestive enzyme, blood biochemistry and liver antioxidant gene expression responses

“…This can be associated with the length of the feeding period. For instance, it was found that stomach pepsin activity and growth performance significantly increased in tilapia fed diets supplemented with malic acid for a 20‐week period (Chen et al, ). In line with the results, it is evident that pepsinogen activity and/or synthesis in fish were enhanced because of acidified diets.…”

“…Organic acids are capable to hinder microbial growth in the feed due to reducing the pH level of the diet and serving as a conserving agent. Furthermore, they can facilitate feed digestion and absorption by chelating various cations and increasing activities of some digestive enzymes for animals (Chen et al, ; Lala, Oso, Okwelum, Ajao, & Adegbenjo, ). Recently, the inclusion of several organic acids or their salts alone or in combination in fish feed has yielded fruitful results on growth performance, feed utilization and disease resistance (Hassaan, Soltan, Jarmołowicz, & Abdo, ; Ng & Koh, ; Ng, Koh, Sudesh, & Siti‐Zahrah, ; Yilmaz, ; Yilmaz, Ergün, & Yıgıt, ; Yilmaz, Sova, & Ergün, ; Yilmaz, ).…”

Feeding malic acid to chickens at slaughter age benefits poultry production and microbial safety in regard to Campylobacter

“…For dairy cows, the feed e ciency was improved, the milk yield was increased and the fat content in the milk was subtly changed (12). The growth and feed utilization were found to be improved in tilapia, but an excess supply would compromise the bene cial effect (10). Despite that inconsistent ndings were reported(28), these results showed the potential bene ts of feeding malic acid to animals when applied with suitable nutritional and managerial measures.…”

“…Malic acid is a type of dicarboxylic organic acid which showed antimicrobial activity (9). Besides, malic acid is an intermediate in metabolic cycles of organisms for energy production, and could aid digestion and absorption by chelating various cations and enhancing the activities of some digestive enzymes (10). Malic acid has been permitted as GRAS (Generally Recognized As Safe), which does not has adverse effects for human intake or animal feeding when properly used.…”

“…Malic acid has been permitted as GRAS (Generally Recognized As Safe), which does not has adverse effects for human intake or animal feeding when properly used. Attempts to provide malic acid to livestock were performed in previous studies, which showed its potential bene ts in promoting the performance of animals and their products (10)(11)(12).…”