World Aquacluture Magazine - September 2020

46 SEP TEMBER 2020 • WORLD AQUACULTURE • WWW.WA S.ORG that fish immunity and fitness is optimum to prevent and attack microbial invasion and disallow opportunistic bacteria from targeting susceptible fish to invade the entire stock (Ashley 2007, Davis et al . 2002, Iguchi et al . 2003). Among proposed remedies is the use of phytobiotics (plant extracts) or probiotics (beneficial bacteria) in aquaculture (Citarasu 2010, Mohapatra et al . 2013). Moreover, global consumption of organic and en- vironmentally friendly foods is increasing. Thus, use of natural and novel products in the treatments of such foods could enhance the consumption of aquaculture produce as a result of the restriction on chemical products in fish farming. Neem Leaf Extraction and Analysis The neem Azadirachta indica tree grows in tropical and arid re- gions and is native to India, Burma and Thailand. Many parts of the tree contain natural organic compounds with insecticidal properties that can be extracted and applied by farmmanagers. Stem bark of the neem tree contains substances with strong anti-inflammatory activity (Van der Nat et al . 1991). Various preparations of neem obtained from its different parts exert antibacterial, anti-malarial, contraceptive and antiulcer activi- ties (Siddiqui et al . 1992). Neem leaves collected from trees on the Lagos State University, Ojo campus were extracted with ethanol (Cowan 1999, Awe et al . 2019a). Samples (40 g) of neem leaf were placed in round-bottom flasks with 150 mL of 95 percent ethanol to which heat (60 C) was applied for four hours. To further reduce extract volume, extracts were vacuum dried. Samples were later concentrated for phytochemical screening by T here has been remarkable progress in African aquaculture over the last decade, with a landmark increase in annual output and number of farmers (FAO 2012). In Africa, catfish farming overtook tilapia culture in 2004, with Nigeria at the forefront of other African coun- tries (FAO 2012). However, in intensive systems, disease outbreaks may lead to a loss of fish and a reduction in farm income (Bondad- Reantaso et al . 2005). Overcrowding, improper handling, temperature fluctuation, poor water quality and nutritional deficiency may result in the weakening of fish and eventually lead to disease outbreaks. Poor sanitation in intensive fish farming could be a source of pathogens that may result in fish mortality (Cabello 2006, Quesada et al . 2013). To avoid financial loss and damages, veterinary drugs are com- monly used in aquaculture to prevent or treat disease outbreaks. Antimicrobials and other veterinary drugs can be added to fish feed, directly to water or injected as a prophylactic, therapeutic or growth enhancer (Rico et al . 2013). However, as a result of awareness and various side effects of veterinary drugs on fish and their environment, fish and humans have become sources of health safety challenge. Vaccine application for the treatment of fish against pathogen proliferation is still widely in used for intensive fish farming. However, commercial vaccines are often too expensive for widespread use by fish farmers and a single vaccine is only effective against just one type of pathogen (Pasnik et al . 2005, Harikrishnan et al . 2011a). Disease management that is preventive is better than veterinary drug use be- cause of their side effects on environment, humans and fish. The alternative method of reducing disease outbreaks is to ensure Histological and Hematological Parameters of Sub-adult African Catfish Inoculated with Staphylococcus aureus and Treated with Neem Leaf Extract Ayofe M. Hammed and Folalu A. Awe TABLE 1. Hematological parameters (mean ± SE) of African catfish, control values, seven days post infection and after GROUP WBC X 109/L HGB g/dL RBC X 10 HCT % MCV fL MCH pg CTR 9.5±0.05 c 8.70±0.05 ab 1.76±0.05 b 25.95±0.05 b 146.55± 0.05 b 42.80±0.05 c PI 11.0±0.50 b 8.00±0.30 ab 1.98±0.17 b 26.50±0.15 b 137.20±0.50 d 73.60±0.05 d T1 7.8±0.05 d 6.70±0.05 b 0.91±0.05 ab 13.60±0.05 d 150.15±0.05 a 43.20±0.05 a T2 11.1±0.55 b 8.90±0.55 ab 2.06±0.11 a 28.50±0.55 b 138.50±0.55 d 40.30±0.05 d T3 15.8±0.5 a 10.70±0.05 a 2.65±0.05 a 37.70±0.05 a 142.50±0.05 c 53.00±0.05 d T4 5.2±0.55 e 6.00±0.05 bc 1.13±0.01 b 17.30±0.05 c 153.20±0.25 a 55.70±0.05 bc ANT 4.6±0.05 f 2.90±0.05 c 0.52±0.05 a 7.00±0.05 e 135.60±0.05 d 51.49±0.05 b MMean values having same superscript along the columns were not significantly different (p> 0.05) Groups: CTR = control, PI = post-infection, T1= 2.5 mg/mL neem leaf extract, T2 = 5.0 mg/mL neem leaf extract, T3 = 7.5 mg/mL neem leaf extract, T4 = 10.0 mg/mL neem leaf extract, ANT = antibiotic.

RkJQdWJsaXNoZXIy MjExNDY=