Growth, physiological, antioxidants, and immune response of African catfish, Clarias gariepinus (B. to dietary clove basil, Ocimum gratissimum, leaf extract and its susceptibility to Listeria monocytogenes infection
ABSTRACT Clove basil, Ocimum gratissimum, is a native plant to Africa and grows virtually in tropical and subtropical regions. It has good aroma and its leaves have become used as a spicy and in traditional medicine. The use of plant leaves in fish diets may deteriorate their growth because it may content anti nutritional factors. Thus, it is better to use plants leaves extract. In the current study, clove basil leaves extract (CBLE) was administrated to African catfish, Clarias gariepinus (B. to evaluate its effect on growth performance, physiological, antioxidants, and innate immunity variables. Fish (10.7+ 0.5g) were fed on diets enriched with 0.0, 5, 10, or 15g CBLE/kg diet for 12 weeks. After the feeding trial, fish were further exposed to pathogenic bacteria (Listeria monocytogenes) for 14 days. Fish performance and feed intake were significantly enhanced with increasing CBLE levels and its optimum level is found to be 12g/kg diet. It is noticed that the dietary CBLE in African catfish diets increased significantly the intestinal villi length, villi width, and absorption area in a dose dependent manner and fish weight was highly correlated with villi length, villi width, and absorption area (R2 0.91, 0.91, and 0.92, respectively) On the other side, Dietary CBLE has significant modulatory effect on hemato and physiological variables of African catfish in a dose dependent manner. In this regard, blood glucose and cholesterol levels decreased significantly; mean while total protein, albumin, and globulin increased significantly in fish fed high CBLE levels (10 15g/kg diet) Furthermore, activities of aspartate aminotransferase and alanine aminotransferase, alkaline phosphatase, urea, and creatinine levels were significantly elevated with increasing dietary CBLE levels and their maximum values were detected in fish fed 15 g CBLE/kg diet. Antioxidants and immunity variables were significantly enhanced by CBLE supplementation. Additionally, fish mortality after bacterial challenge was highest in fish fed the control diet (85% than those fed CBLE enriched diets. The lowest fish mortality was observed in fish fed 15g CBLE/kg diet (13.5% This study evoked that CBLE administration enhanced the performance, feed utilization, antioxidant, and innate immunity properties of African catfish with optimum level of 12g/kg diet. Also, its supplementation enhanced fish challenge against L. monocytogenes. HIGHLIGHTSAfrican catfish fed on diets enriched with ethanolic extract of clove basil leaves (CBLE) for 12 weeks.After CBLE feeding, fish were exposed to pathogenic bacteria, Listeria monocytogenes, for 14 days.Dietary CBLE has significant modulatory effect on hemato and physiological variables of African catfish.Also, CBLE supplementation improved significantly fish performance and welfare up to 12g/kg diet.CBLE supplement has antioxidant and immuno activity and elevated the fish resistance against pathogenic bacteria.
Fish shellfish immunology