Influence of Ulva seaweed meal on immune responses in GIF tilapia
The immuno physiological responses of GIF tilapia fed
Ulva meal are given Fig 1-5. Significant differences in the catalase activity, super oxide dismutase, respiratory burst activity, serum protein values and myeloperoxidase activity were observed between the treatments and control. The increased values of catalase, SOD, respiratory burst activity, serum protein values and myeloperoxidase activity were observed in fermented
Ulva supplemented diet at 10 % inclusion level when compared with control and other treatments.
Increased catalase activity (0.88±0.02 u/mg of protein), SOD (3.18±0.22 u/mg of protein), RBA (0.88±0.02 units/ml), SPV (0.68±0.01 mg/ml) and MPA (6.72±0.04 u/ml of enzyme) values were recorded in GIF tilapia fed with fermented
Ulva meal at 10% inclusion level followed by UF5 diet (CAT-0.82±0.01 u/mg of protein, SOD-3.13±0.12 u/mg of protein, RBA-0.81±0.02 units/ml, SPV-0.67±0.03 mg/ml and MPA-6.53±0.18 u/ml of enzyme), UR5 diet (CAT -0.66±0.04, SOD-2.62±0.06 u/mg of protein, RBA-0.69±0.02 units/ml, SPV-0.67±0.03 mg/ml and MPA-5.39±0.15 u/ml of enzyme), control diet (CAT-0.56±0.28 u/mg of protein, SOD-2.32±0.09 u/mg of protein, RBA-0.64±0.04 units/ml, SPV-0.63±0.05 mg/ml and MPA-5.04±0.15), UF15 diet (CAT-0.38±0.03 u/mg of protein, SOD-1.94±0.00 u/mg of protein, RBA-0.46±0.03 units/ml, SPV-0.24±0.02 mg/ml and MPA - 3.48±0.22 u/ml of enzyme), UR10 diet (CAT -0.35±0.04 u/mg of protein, SOD-1.66±0.02 u/mg of protein, RBA-0.59±0.02 units/ml, SPV-0.17±0.03 mg/ml and MPA-2.30±0.16 u/ml of enzyme) and UR15 diet (CAT -0.31±0.02 u/mg of protein, SOD-1.29±0.05, RBA-0.44±0.06 units/ml, SPV-0.12±0.01 mg/ml and MPA -1.05±0.02 u/ml of enzyme).
Similarly, Shrimp fed with
U.
pinnatifida at 6% inclusion showed enhancement in SOD activity
(Niu et al., 2015). Grey mullet fed with
Ulva rigida extract at 10 mg/kg inclusion showed increased immune reponses
(Akbary and Aminikhoei, 2018). Red seabream fed with
Ulva meal at 5% inclusion showed enhancement in complement activity and disease resistance
(Satoh et al., 1987). Nile tilapia fed with
Ulva spp.
(Ulva rigida and
Ulva lactuca) at 10 % inclusion showed improved lysozyme or peroxidase activity
(Valente et al., 2016). Rainbow trout fed with
Ulva intestinalis extract at 1.5% inclusion showed enhancement in lysozyme and complement activity
(Safavi et al., 2019). Nile tilapia fed with
Ulva fasciata extract at 100 mg/kg inclusion showed enhanced antioxidant enzyme activities of superoxide dismutase and catalase activity
(AboRaya et al., 2021). Shrimp fed with
U.
pinnatifida at 6% inclusion showed enhanced SOD activity
(Niu et al., 2015). Nile tilapia fed with
U.
clathrata extract inclusion showed increased immune responses
(Del Rocio Quezada-Rodriguez and Fajer-Avila, 2017). Juvenile grey mullet (
Mugil cephalus) fed with
Ulva rigida extract at 10% inclusion showed stimulated lysozyme, phagocytic and respiratory burst activity
(Akbary and Aminikhoei, 2018).
SOD and CAT are important enzymes in antioxidant defence system as they play a key role in removing free radicals and toxicity of drugs and chemicals
(Farombi et al., 2007). Increased SOD with sodium alginate due to the high presence of superoxide anions in polysaccharides
(Yeh et al., 2008; Lee et al., 2017). Polysaccharides stimulate immune systems and can improve different parts of the innate immunity such as lysozyme, ACH50, anti-protease activities, phagocytic activity, respiratory burst and phenoloxidase enzyme activities
(Mohan et al., 2019). Presence of some bioactive compounds such as palmitic acid
(Aparna et al., 2012; Raman et al., 2012; Wong et al., 2017), oleic acid
(Hashimoto et al., 2006), clionasterol
(Raman et al., 2012), phytol
(McGinty et al., 2010; Santos et al., 2013) and neo-phytadiene
(Raman et al., 2012) improved immune response in fishes. Improving immune system of fish may act indirectly to promote growth performance
(Hindu et al., 2019; Mohan et al., 2019). Sulfated polysaccharides can stimulate the immune response by binding to cellular receptors of the immune system
(Teruya et al., 2009; Jiao et al., 2011). Extracts derived from seaweeds are natural sources of antioxidants and they neutralize free radicals
(Goiris et al., 2012). Ulva spp contains carotenoids, minerals and vitamins, which affect the health of and improve the immunity fish. Similarly this study also proved GIF tilapia fed with fermented
Ulva meal reflected positive immune responses performance as per the result given in Fig 1-5.
Influence of Ulva meal on the stress responses of GIF tilapia
The stress responses observed in GIF tilapia fed
Ulva based diets given in Table 4. Decreased glucose level (83.18±0.61) was recorded in GIF tilapia fed with fermented
Ulva meal at 10% inclusion level. The triglycerides (196.85±0.41) and cholesterol (151.67±1.52) were observed highest in fish fed fermented
Ulva meal at 10% diet. Increased glutathione peroxidase values (14.13±0.17) were observed in GIF tilapia fed with fermented
Ulva meal at 10% incorporated diet.
Lower glucose level represents lower stress level in fish. Plasma cholesterol and triglyceride reflect nutritional status of fish
(Pourmozaffar et al., 2019). Similarly, the significant decreases in glucose level in the blood of yellow catfish, rohu and red sea bream (
Pagrus major) fed with dietary fucoidan
(Yang et al., 2014; Mir et al., 2017; Sajina et al., 2019; Sony et al., 2019) have been reported. 5 %
Ulva lactuca fed fish showed improved stress response after a 5-min air exposure test, prior to termination of the feeding trial
(Wassef et al., 2013). Rainbow trout fed with
Ulva intestinalis sulfated polysaccharide extract
at 1.5% inclusion showed decreased amount of cortisol
(Safavi et al., 2019). Cortisol and glucose are indicator of fish status during acute or chronic stress
(Barton and Iwama, 1991). Similarly this study also proved that GIF tilapia fed with fermented
Ulva meal reflected reduced stress responses and positive enhancement in antioxidant enzyme activities.