The RBCs showed a dramatic elevation (
P<0.05 in fish which used probiotic (Table 2). The ALT and glucose levels dramatically reduced (
P<0.05) in T1, T2 and T3 fish groups compared to the control group (T0). Furthermore, the AST and alkaline phosphatase decreased in the various tested groups relative to control. The supplementation of probiotic dramatically elevated the serum total protein and albumin and globulin levels (
P<0.05) relative to the control group after 56 days. The lowest levels of creatinine were observed in T1, T2 and T3. Hemoglobin (Hb) (g dl
-1), Hematocrit (Hct) (%), Mean corpuscular hemoglobin (MCH) (pg) and mean corpuscular hemoglobin concentration (MCHC) (%) increased. While Mean corpuscular volume (MCV) (fl) decreased. Urea and Uric acid decreased in treatment groups relative to the control group. The haemato-biochemical parameters are critical in determining the health of aquatic animals. All of the haemato-biochemical parameters measured in this study on red tilapia were within normal limits, compared to the earlier research done by
Rathore et al., (2021). Hemato-biochemical parameters are useful for assessing fish health, nutritional status and ability to adjust to their environment (
Abdel-Tawwab, 2016;
Adeshina et al., 2019).
Total protein, albumin and globulin levels were greatest in the probiotics treatments, showing that the probiotics-fed fish were better than the control group. As probiotic levels rose, so did these markers. The results are comparable to those of
Kamgar and Ghane (2014) and
Nargesi, Falahatkar (2020), however they diverge at lower glucose concentrations. The usage of probiotics, which enhance the intestinal flora and consequently digesting and nutrient absorption, may be responsible for the protein profile
(Eshak et al., 2010). Fish have a considerable immune response, as evidenced by the rise in total protein, albumin and globulin levels (
Al-Dohail et al., 2009).
The findings revealed that fish fed probiotics had considerably greater RBC, Hb and Ht levels than the control group. These results demonstrated that Red tilapia without anemia signs had increased hematological parameters due to feeding probiotics. These findings suggest improved fish health since they are associated with increased erythropoiesis and hemosynthesis. According to earlier studies (
Mişe Yonar et al., 2013;
Priyadarsini, 2014;
El-Barbary, 2018;
Enis Yonar et al., 2019; Mohamed et al., 2020), adding curcumin to the diet enhances hematological markers in a range of fish species. These outcomes provide credence to those studies.
Systematically evaluated markers of the status of the liver are the aminotransferases AST, ALT and ALP
(Murray et al., 2003; Molina et al., 2005). The results show that the fish in the current research weren’t under any stress.
Fadl et al., (2020) and
Xu et al., (2020) showed the blood AST, ALT and ALP activity of fish fed probiotic-supplemented diets was dramatically reduced. According to
Eissa et al., (2022c), P. vannamei given various dosages of probiotic supplements had a reduction in AST, ALT and ALP levels in contrast to the control.
Different investigators have reported that liver enzymes levels vary depending on the used probiotics used Their levels were dramatically decreased in tilapia plasma after dietary treatment of two probiotic bacteria strains (
Micrococcus luteus and
Pseudomonas spp.), which has led to the discovery that their levels differ depending on the probiotics utilized in research (
Abd El-Rhman et al., 2009). However, in a different research, fish that received dietary supplements including
Lactobacillus plantarum,
Lactobacillus acidophilus, or
Saccharomyces cerevisiae and olive flounder (
Paralichthys olivaceus), had considerably higher levels of AST, ALT and ALP
(Harikrishnan et al., 2010).
The findings of the current study concur with those of
Hassanien et al., (2017) and
Kurdomanov et al., (2019), who discovered that probiotic-treated diets decreased AST, ALT and ALP levels when as compared to control diets, but they disagree with
Al-Hisnawi and Beiwi (2021), who discovered that diets supplemented with
Bacillus subtilis and
Ghiasi, Binaii (2018), who reported that differences between studies might be explained by differences in the probiotics’ kind, amount, fish species tested, treatment period and/or external conditions
(Eissa et al., 2022b).
The findings showed that probiotic supplementation increased mean corpuscular hemoglobin (MCH) and mean corpuscular hemoglobin concentration (MCHC). The average corpuscular volume decreased (MCV) as well. These findings contradicted those of
Knoph and Thorud (1996), who reported a rise in MCV.
In contrast, the probiotic supplemented groups showed a reduction in their levels of creatinine, urea and uric acid. In contrast to
Farghaly et al., (1973) who showed no change in creatinine, urea and uric acid upon consuming the probiotic reveling its safety for the fish’s kidney metabolic function.
Histological results of the intestinal villi of the T2 and T3 groups were branched, markedly lengthened and the apical portion of the T3 group’s intestinal villi had moderate sloughing. In the controlled condition, the intestinal villi’s apical portion was clearly sloughing (T0) as shown in (Fig 1, 2). Fish growth, illness resistance and feed consumption are all greatly impacted by the growth of the internal organs, particularly the gut. In the current investigation, the histology of the tilapia treated with commercial probiotics revealed noticeably better intestinal developments than the control group. The current study’s findings are in line with those of other research in terms of the beneficial effects of probiotics during larval stages and beyond, whether as a feed addition, a water additive, or even as an enrichment to live foods (rotifer, Artemia,
etc).
(Lotfy, 2015;
Kuebutornye et al., 2019; Eissa et al., 2022b).