Effects of Dietary Inclusion of Various Additives on Growth Performance, Hematological Parameters, Fatty Acid Composition, Gene Expression and Histopathological Changes in Juvenile Olive Flounder Paralichthys olivaceus

Abstract

This feeding experiment was conducted to investigate the effects of dietary inclusion of various additives on growth performance, hematological parameters, fatty acid composition, gene expression and histopathological changes in juvenile olive flounder (Paralichthys olivaceus). Eleven isonitrogenous (49% crude protein) and isolipidic (10% crude lipid) experimental diets were formulated: no additives (Con); 5% kelp meal (Ke); 10% krill meal (Kr); 1% garlic powder (Ga); 1% citrus meal (Ci); 3% onion powder (On); 1% ginger powder (Gi); 1% mugwort powder (Mu); 1% licorice powder (Li); 1% wasabi powder (Wa); and a mixture (Mix) of these additives. Three replicate groups of juvenile flounder (average weight of 8.5 g) were fed one of the experimental diets to visual satiety twice a day for 15 weeks. The dietary inclusion of additives did not affect survival, weight gain, specific growth rate feed efficiency, daily feed intake, daily protein intake, protein efficiency ratio, hepatosomatic index and visceralsomatic index of the fish. Plasma triglyceride levels were significantly lower in fish fed the Ke, Ga, On, Gi, Mu, Li, and Mix diets than in fish fed the control diet. Plasma glucose, glutamic oxaloacetic transaminase and total cholesterol did not differ among dietary treatments. No significant difference was observed in fatty acid composition and lipid content of the dorsal muscle in fish fed the experimental diets. Myosin gene expression did not differ significantly among treatments after 5 weeks but was significantly lower in fish fed the Kr, Ci, Li, and Mix diets than in control group after 15 weeks. Histopathological analysis showed mild gill hyperplasia and mild necrosis of liver parenchymal cells in several individuals of each experimental group. These conditions were also observed in the control group and were not thought to be related to the inclusion of feed additives. The present findings indicate that the dietary inclusion of additives did not affect growth performance, fatty acid composition, gene expression, and histopathological changes in juvenile flounder. However, plasma triglyceride content may be reduced by supplementation with 5% kelp meal, 3% onion powder, 1% garlic powder, 1% ginger powder, 1% mugwort powder, and the additive mixture.

Dietary inclusion effect of various sources of phyto‐additives on growth, feed utilization, body composition, and plasma chemistry of olive flounder (Paralichthys olivaceus), and challenge test against Edwardsiella tarda compared to a commercial probiotic (super lacto®)

“…Inclusion of phyto‐additives (YC, GG, and BB) in diets did not bring about any distinctive difference in growth performance (weight gain and SGR) of olive flounder in the present study, which is consistent with Kim et al (2011)'s study, in which dietary supplementation of various additives containing 3% onion powder, 1% citrus meal, 5% kelp meal, 10% krill meal, and 1% of each mugwort, wasabi, licorice, garlic, and GG powders, and their mixtures had no influence on the growth performance of olive flounder in the 15‐week feeding experiment. Similarly, Cho et al (2013) proved that dietary inclusion of Scutellaria baicalensis extract at doses of 0.5%, 1%, 2%, 3%, and 5% for 8 weeks did not affect weight gain in olive flounder.…”

“…Likewise, oral administration of diets containing 1% ethanol extracts of YC, GG, and 0.5% SUP brought about no difference in feed consumption, FE, or PR of olive flounder (Yin et al, 2021). Consistently, another study (Kim et al, 2011) demonstrated that feed utilization of olive flounder was not influenced by diets supplemented with various plant‐based feed additives. In contrast, Lee et al (2021) found that dietary inclusion of 1% of garlic, GG, BB, tomato, onion, and YC juice processing by‐product powders enhanced feed consumption, FE, PER, and PR of rockfish in the 7‐week feeding trial.…”

Nutritional Characteristics of Juvenile Black Rockfish Sebastes schlegeli Fed a Diet of Fig Leaf Extract

“…. (Fermáandez-Navarro et al, 2008;Kim et al, 2011), (Sebastes schlegeli) , , , Chang, 1994;Bae et al, 2000;Park et al, 2008;Lee et al, 2008;Lim et al, 2009;Seo et al, 2009;Hwang et al, 2012). (Kim, 2001;Jeong et al, 2002) (Kang and Jung, 1995) (Ficus carica L.) 600 (William et al, 1968;, 1980;Vinson, 1999), , ( ) (Shin, 1997).…”