Source diversity of Artemia enrichment boosts goldfish (Carassius auratus) performance, ß-carotene content, pigmentation, immune-physiological and transcriptomic responses.

This study aimed to assess the impact of spirulina and/or canthaxanthin-enriched Artemia on the goldfish (Carassius auratus) growth, pigmentation, blood analysis, immunity, intestine and liver histomorphology, and expression of somatolactin (SL) and growth hormone (GH) genes. Artemia was enriched with spirulina and/or canthaxanthin for 24 h. Goldfish (N = 225, 1.10 ± 0.02 g) were tested in five experimental treatments, three replicates each: (T1) fish fed a commercial diet; (T2) fish fed a commercial diet and un-enriched Artemia (UEA); (T3) fish fed a commercial diet and spirulina-enriched Artemia (SEA); (T4) fish fed a commercial diet and canthaxanthin-enriched Artemia (CEA); and (T5) fish fed a commercial diet and spirulina and canthaxanthin-enriched Artemia (SCA) for 90 days. The results showed that the use of spirulina and/or canthaxanthin increased performance, ß-carotene content and polyunsaturated fatty acids of Artemia. For goldfish, T5 showed the highest growth performance, ß-carotene concentration and the lowest chromatic deformity. T5 also showed improved hematology profile, serum biochemical, and immunological parameters. Histomorphology of the intestine revealed an increase in villi length and goblet cells number in the anterior and middle intestine, with normal liver structure in T5. SL and GH gene expression in the liver and brain differed significantly among treatments with a significant increase in enriched Artemia treatments compared to T1 and T2. In conclusion, the use of spirulina and/or canthaxanthin improved performance of Artemia. Feeding goldfish spirulina and/or canthaxanthin-enriched Artemia improved performance, ß-carotene content, pigmentation, health status and immune-physiological response.

Dietary Lactobacillus acidophilus ATCC 4356 Relieves the Impacts of Aflatoxin B1 Toxicity on the Growth Performance, Hepatorenal Functions, and Antioxidative Capacity of Thinlip Grey Mullet (Liza ramada) (Risso 1826).

Dietary Lactobacillus acidophilus ATCC 4356 was used to relieve the impacts of aflatoxin B1 toxicity on the performances of Liza ramada. The control diet was without any additives, while the second and third diets were supplemented with aflatoxin B1 at 0.5 and 1 mg/kg. The fourth diet was supplemented with Lb. acidophilus ATCC 4356 at 1 × 106 CFU/mL per kg diet, while the fifth with aflatoxin B1 at 1 mg/kg and Lb. acidophilus ATCC 4356 at 1 × 106 CFU/mL per kg diet. The growth performance markedly increased (p < 0.05) in L. ramada fed Lb. acidophilus ATCC 4356, while aflatoxin B1 at 0.5 and 1 mg/kg groups showed a severe reduction. The red blood cells, hemoglobulin, hematocrit, and white blood cells were markedly increased in L. ramada fed Lb. acidophilus ATCC 4356 while decreased (p < 0.05) in fish fed aflatoxin B1 at 0.5 and 1 mg/kg. The blood total protein and albumin were markedly increased (p < 0.05) in L. ramada fed Lb. acidophilus ATCC 4356 while reduced in aflatoxin B1 at 0.5 and 1 mg/kg groups. The levels of total cholesterol and triglycerides were meaningfully increased in fish of the Lb. acidophilus ATCC 4356 and aflatoxin B1 at 1 mg/kg groups while decreased in aflatoxin B1 at 0.5 and 1 mg/kg groups. Alanine aminotransferase, aspartate aminotransferase, creatinine, and urea levels were markedly decreased (p < 0.05) in fish-fed Lb. acidophilus ATCC 4356 while increased in aflatoxin B1 at 0.5 and 1 mg/kg groups. The highest levels of blood glucose and cortisol were seen in fish contaminated with aflatoxin B1 at 1 mg/kg, while the lowest levels were observed in the fish fed Lb. acidophilus ATCC 4356 group (p < 0.05). The catalase and superoxide dismutase were markedly enhanced in the Lb. acidophilus ATCC 4356 group and severely declined in aflatoxin B1 at 0.5 and 1 mg/kg groups (p < 0.05). The malondialdehyde level was markedly reduced in fish fed Lb. acidophilus ATCC 4356 with or without aflatoxin B1 at 1 mg/kg diets while increased in fish contaminated with aflatoxin B1 at 0.5 and 1 mg/kg (p < 0.05). The control group had lower malondialdehyde levels than the aflatoxin B1 at 1 mg/kg group and higher than the Lb. acidophilus ATCC 4356 with or without aflatoxin B1 toxicity (p < 0.05). Histopathological examination revealed impaired intestines and livers in fish contaminated with aflatoxin B1 while Lb. acidophilus ATCC 4356 relieves the inflammation and protected the intestines and livers. In conclusion, dietary Lb. acidophilus ATCC 4356 is recommended to relieve the impacts of aflatoxicosis-induced hepatorenal failure and oxidative stress in L. ramada.

Acute ammonia exposure combined with heat stress impaired the histological features of gills and liver tissues and the expression responses of immune and antioxidative related genes in Nile tilapia.

Ammonia exposure can be considered more stressful for aquatic animals when it coincides with high temperature. This study was conducted to detect the effects of ammonia exposure and heat stress and their interactions on the histological features of gills and liver tissues and the expression responses of immune and antioxidative related genes in Nile tilapia. Thus, 180 fish were divided into four groups (triplicates), where the first and third groups were kept in clean water without total ammonium nitrogen (TAN) exposure. At the same time, the second and fourth groups were exposed to 5 mg TAN/L. After seven days, the water temperature was raised in the third (without ammonia toxicity) and fourth (exposed with 5 mg TAN/L) groups up to 32 °C and kept under these conditions for 24 h. While the first (without ammonia toxicity) and second (exposed with 5 mg TAN/L) groups were kept under optimum water temperature (27.28 °C) then gills and liver tissues were dissected. Marked upregulation of keap1 was seen in the gills of fish exposed to ammonia/heat stress. The expression of mRNA levels for nrf2, nqo-1, cat, and gpx genes were downregulated in all stressed groups, with the lowest was recorded in the ammonia/heat stress group. The transcription of ho-1 was upregulated in the ammonia and heat stress groups while downregulated in the ammonia/heat stress group. The transcription of the complement C3 gene was downregulated in the livers of heat stress and ammonia/heat stress groups, while the lysozyme gene was downregulated in the ammonia/heat stress group. The mRNA expression levels of nf-κB, il-1ß, and tnf-α genes were higher in the ammonia group than in the heat stress group. The highest transcription level of nf-κB, il-1ß, tnf-α, il-8, and hsp70 genes and the lowest C3 and lysozyme genes were observed in fish exposed to ammonia/heat stress. The co-exposure to ammonia with heat stress triggered degeneration of primary and secondary gill filaments with telangiectasia and vascular congestion of secondary epithelium while, the liver showed hepatic vascular congestion and visible necrotic changes with nuclear pyknosis. In conclusion, the combined exposure of ammonia and heat stress induced oxidative stress, immunosuppression, and inflammation in Nile tilapia.

Synergistic Effects of Selenium and Zinc Oxide Nanoparticles on Growth Performance, Hemato-biochemical Profile, Immune and Oxidative Stress Responses, and Intestinal Morphometry of Nile Tilapia (Oreochromis niloticus).

This study was aimed to investigate the synergistic effects of selenium (Se-NP) and zinc oxide (ZnO-NP) nanoparticles on growth performance, hemato-biochemical profile, immune and oxidative stress responses, and intestinal morphometry of Nile tilapia (Oreochromis niloticus). Monosex Nile tilapia (12.50 ± 1.03 g, N= 180) were randomly allocated into 4 groups in triplicates. Fish were fed diet supplemented with 0 Se-NP and Zn-NP (control group, CG), while fish in the other experimental groups were fed diet supplemented with 1 mg/kg diet Se-NP (Se-NP group), 10 mg/kg diet ZnO-NP (Zn-NP group), and a mixture of 1 and 10 mg/kg diet Se-NP and Zn-NP, respectively (Se/Zn-NP group) for 60 days. Fish fed diet containing Se-NP, Zn-NP, and Se/Zn-NP showed higher final body weight, weight gain, weight gain rate, specific growth rate, and lower feed conversion ratio with respect to CG (P<0.05) with the highest being in fish fed with Se/Zn-NP. Fish fed with Se/Zn-NP showed higher hemoglobin, red blood cells, and globulin (P<0.05). The highest phagocytic activity, phagocytic index, lysozyme activity, and immunoglobulin M was recorded in fish that received Se/Zn-NP followed by Se-NP, Zn-NP, and the lowest in CG (P<0.05). Fish that received diet supplemented with Se-NP, Zn-NP, and Se/Zn-NP significantly (P<0.05) increased superoxide dismutase and catalase while reduced malonaldehyde activity compared to CG. Intestinal morphometry revealed significantly (P<0.05) increased villi length and goblet cells number in fish fed with Se-NP and/or Zn-NP. In conclusion, dietary supplementation of Nile tilapia with Se-NP and Zn-NP induces synergistic effects that improve growth performance, blood health, and intestinal histomorphology.

Mannan Oligosaccharide Enhanced the Growth Rate, Digestive Enzyme Activity, Carcass Composition, and Blood Chemistry of Thinlip Grey Mullet (Liza ramada).

Mannan oligosaccharide (MOS) is prebiotic with high functionality in aquaculture. The current study investigated the potential roles of MOS on the growth performance, digestive enzyme activity, carcass composition, and blood chemistry of Thinlip grey mullet (Liza ramada). Four tested diets with 34.49% crude protein and 6.29% of total lipids were prepared and fortified with 0, 0.5, 1, and 2% MOS. Fish of initial weight = 5.14 ± 0.11 g/fish were distributed in 12 hapas (0.5 × 0.5 × 1 m) at 15 fish per hapa (triplicates) and fed the test diets to the satiation level two times a day (08:00 and 15:00) for eight weeks. At the end of the trial, all fish were weighed individually for growth performance calculation. Blood was collected to check blood chemistry traits, and intestines were dissected for digestive enzyme analysis. Fish treated with MOS had marked enhancement in the final body weight, feed conversion ratio, protein gain, and protein retention regardless of inclusion dose (p < 0.05). The weight gain, specific growth rate, and protein efficiency ratio were meaningfully enhanced by including MOS at 0.5 and 1%, followed by fish fed with 2% MOS, while the lowest values were in the control group (p < 0.05). Insignificant influences of MOS were seen on the chemical composition of carcass components (moisture, crude protein, total lipids, and ash) (p > 0.05). Fish treated with MOS at 0.5 and 1% had marked enhancement in the amylase, lipase, and protease activities regardless of inclusion dose (p < 0.05). The blood total protein and albumin levels were meaningfully enhanced by including MOS at 0.5 and 1%, followed by fish fed with 2% MOS, while the lowest values were in the control group (p < 0.05). The blood globulin was significantly enhanced in fish fed 1% MOS than fish treated with 0, 0.5, and 2% of MOS (p < 0.05). The blood lysozyme activity was meaningfully enhanced by including MOS at 1%, followed by fish treated with 0.5 and 2%, while the lowest values were in the control group (p < 0.05). Phagocytic activity and phagocytic index were markedly improved in fish treated with 1 and 2% MOS, followed by those fed 0.5% compared with fish fed MOS-free diet (p < 0.05). Superoxide dismutase and glutathione peroxidase were markedly improved in fish treated with 1, and 2% MOS, followed by those fed 0.5% compared with fish fed MOS-free diet (p < 0.05). Dietary MOS (0.5, 1, and 2%) meaningfully enhanced catalase activity while decreased the malondialdehyde concentration (p < 0.05). In summary, dietary MOS is required at 0.5-1% for enhancing the growth rate, feed efficiency, digestive enzyme activity, blood chemistry, and antioxidative capacity of grey mullet.