Impact of Fermented Mulberry Leaf and Fish Offal in Diet Formulation of Indian Major Carp (Labeo rohita)

From waste to feed: Microbial fermented abalone waste improves the digestibility, gut health, and immunity in marron, Cherax cainii

New aquafeed ingredients produced by a circular economy approach are the opportunity for sustainable and resilient aquaculture. In the light of this approach, the mixture of abalone waste and Sargassum spp (9:1) fermented by Saccharomyces cereviceae and Lactobacillus casei (Yakult®) (FMAS) were used to replace 0% (FMAS0), 25% (FMAS-25), 50% (FMAS-50), 75% (FMAS-75), and 100% (FMAS-100) of fishmeal (FM) protein in marron, Cherax cainii diet. The marron was fed these diets in triplicate for 90 days. Growth, feed utilization and protein efficiency ratio were unchanged in marron-fed all test diets. Improvement in apparent protein digestibility was aligned with an increase in the size and number of B-cells in the hepatopancreas. Most of the immune responses, except for haemocyte clotting time, hyaline cells and neutral red retention time (NRR time) were unchanged by 42- and 90-days feeding trials compared to those of the control group. 90 days post-feeding marron with FMAS25 showed a lower haemocyte clotting time than the post 42 days feeding marron with the same diet. Hyaline cells increased in marron fed FMAS75 for 90 days compared to marron fed the same diet for 42 days. The challenge test involved injecting marron with Vibrio mimicus resulted in a 100% survival rate after 96 h of exposure. During the challenge test, phagocytosis activity in 24 and 48-h post-challenged marron fed FMAS75 decreased which recovered after 96 h post-challenge. Marron fed FMAS50 also recorded a significantly higher proportion of granular cells after 24 h and NRR time at 96 h compared with that of other treatments. Given the above indicators of bio-growth, feed efficiency and immune responses, total replacement of FM protein of marron practical feed with FMAS are considered feasible and optimum to maintain health status and resistance to disease.

Influence of dietary fermented Folium mori on growing performance, lipometabolism and disease resistance of golden pompano Trachinotus ovatus

Folium mori, as a plant unconventional feedstuff, are comparatively available due to cost-effectiveness, whereas their usage as aquafeed in pure form is restricted owing to the great fibre and antinutritional factors (ANFs) levels. Thereof, several methods of processing are introduced to remove antinutrient factors from the plant products, leading to improvement of bioactivity and digestibility. The assay was completed to evaluate the method of fermentation and the role of dietary fermented Folium mori (FFM) in golden pompano. Each of 5 diets with FFM at contents of 0.0%, 2.0%, 4.0%, 6.0% and 8.0% (D0.0, D2.0, D4.0, D6.0 and D8.0) was fed to the fishes with original body weight of 9.02g in triplicate sea cages for 56 days. The outcomes revealed that FFM in D4.0 and D6.0 elevated the growing performance of the fishes and the growing performance of D4.0 was remarkably improved in contrast to D0.0 and D2.0(P < 0.05). Whole body lipidic levels were obviously elevated when the diet FFM contents were below 8.0% (P < 0.05), whereas the contents of muscular moisture were generally reduced. In addition, FFM significantly increased serum high density lipoprotein (HDL) and remarkably reduced overall triglyceride (TG) in D2.0 to D6.0(P < 0.05). Moreover, FFM remarkably elevated the activities of lipase of stomach and hepatopancreas in contrast to D0.0 (P < 0.05) as well as intestinal tryptic enzyme in the entire FFM groups (P < 0.05). Eventually, FFM remarkably ameliorated disease-resistant characters of golden pompano to Vibrio harveyi in D4.0 and D6.0 (P < 0.05) and the RPS in D4.0 was optimal. To sum up, the present research displayed favorable role of FFM in growing performance, digestion, lipometabolism and disease-resistant characters, and the recommendation as to the supplementation content of diet FFM in compound feed of juvenile golden pompano is 4.0% as per the experiment status herein.

Mulberry leaf meal: A potential feed supplement for juvenile Megalobrama amblycephala "Huahai No. 1"

This study was performed to evaluate the potential application of mulberry leaf meal (ML) and fermented mulberry leaf meal (FML) as feed supplements in aquatic animals for developing varieties of practical and economical feed ingredients. Juveniles Megalobrama amblycephala were fed a basal diet (35.7% crude protein, 10.4% crude lipid; control group) supplemented with 2.22% and 4.44% mulberry leaf meals (ML2, ML4) and fermented mulberry leaf meals (FML2, FML4) for 8 weeks. Generally, the two-way ANOVA showed the supplementation level exhibited a prominent effect on the growth performance and physiological status of fish. Furthermore, the two-way ANOVA showed the supplementary fermented mulberry leaf meal increased plasma complement 4 (C4) content (P < 0.05). The weight gain rate (WGR, 145.87%) and the specific growth rate (SGR, 1.63%) were significantly increased in FML2 group compared with the control group (P < 0.05). The muscle crude lipid content and hepatosomatic index (HSI) were higher in FML2 group than that in ML2 group (P < 0.05). The hepatic GSH content in ML4 group and CAT, T-SOD activities in FML4 group were significantly increased compared with the control group (P < 0.05). The hepatic MDA content in FML4 group was significantly decreased compared with the FML2 group (P < 0.05). Total cholesterol (TC) contents showed a significant decrease in ML4 and FML4 groups compared with the control group (P < 0.05). Regarding the gene expression, sirtiun 1 (Sirt1) gene expression was elevated in FML2 group compared with the ML2 group (P < 0.05). Compare to the control group, FML2 diet significantly increased the expression of i-kappa-B alpha (IKBα) gene in liver, and decreased the expression of forkhead box O1 α (FoxO1α), toll-like receptors 4 (TLR4) and nuclear factor-kappa B (NF-κB) genes (P < 0.05). In conclusion, 2.22% FML promoted the growth performance of M. amblycephala and enhanced the anti-inflammatory responses by inhibiting TLR4/NF-κB signaling pathway. On the other hand, 4.44% FML reduced plasma lipid content (hypolipedemic effect) and improved the hepatic antioxidant capacity of M. amblycephala.

Effects of mulberry (Morus alba L.) Leaf extracts on growth, immune response, and antioxidant functions in nile tilapia (Oreochromis niloticus)

This study evaluates how white mulberry (Morus alba L.) leaf extracts affect the growth, antioxidant activity, and immune response in Nile tilapia Oreochromis niloticus. Mulberry leaf extracts were obtained through aqueous extraction (AE) and ethanol extraction (EE). Powder of mulberry leaf (PML) was added directly to feed and compared with the effects of feeds supplemented with the different extracts. Fish were divided into eight groups for an 8-week feeding trial where they were fed the basal diet or supplementation with 10% PML, 10% AE, 20% AE, 40% AE, 10% EE, 20% EE, or 40% EE. The inclusion of mulberry leaf extract obtained with either method showed better effects on fish growth performance, antioxidant activities and acid phosphatase activity (ACP) in serum, immune cytokine expression, and intestinal morphology as compared with controls or fish fed the 10% PML diet. The specific growth rate was significantly higher in the 10% AE, 10% EE, and 20% EE groups compared with all other groups (P<0.05). Catalase activity was significantly greater in most groups fed an extract, and in the 10% PML group, when compared with controls. Similarly, ACP, interleukin (IL)-1, and IL-2 expression was significantly increased in groups fed an extract, and in the 10% PML group, when compared with controls (P<0.05). IL-1, IL-2, IL-10, and Toll-like receptor 2 expression was significantly greater in the 10% EE group than in the 10% PML and 10% AE groups (P<0.05). Villus length in the middle intestine was significantly increased in the 10% AE and 10% EE groups compared with controls and the 10% PML group (P<0.05). Thus, 10% mulberry leaf ethanol extract added to feed is recommended for enhancing the growth rate and health of cultured Nile tilapia.

Impact of Yeast Fermented Poultry by-Product Meal on Growth, Digestive Enzyme Activities, Intestinal Morphometry and Immune Response Traits of Common Carp (Cyprinus carpio)

The current study was carried out to investigate the effects of Saccharomyces cerevisiae-fermented poultry by product meal (PBM) on growth performance, micromorphological, and immunological changes in common carp. Five experimental diets were prepared to include fermented PBM at 0, 5, 10, 15, and 20 % level in the diet of common carp (4.91±0.01 g). The fish were reared for 90 days on these diets. The obtained results revealed that yeast fermented PBM significantly changed the final body weight (FBW), weight gain (WG), specific growth rate (SGR), feed intake (FI), and feed conversion ratio (FCR) of the fish in a dose dependent manner (P<0.05). Fish fed 20 % fermented PBM showed the highest FBW, WG, SGR, FI, and lowest FCR. However, whole body composition did not vary significantly among fish fed different diets (P>0.05). Dietary yeast fermented PBM at 10 and 20 % level significantly increased the lipase, amylase, and protease activities than the other groups (P<0.05). The anterior, middle, and posterior intestinal villus length was significantly increased in fish fed fermented PBM at 15 and 20 % level when compared to the other groups (P<0.05). The number of goblet cells was significantly increased in the middle section of intestine in fish fed yeast fermented PBM at 20 % level, while in the posterior region of intestine the number of goblet cells was significantly increased in fish fed yeast fermented PBM at 15 and 20 % level (P<0.05). The histomorphology of intestine showed an increased length, branching and density of intestinal villi in fish fed yeast fermented PBM diets. Most of the measured blood parameters showed insignificant (P>0.05) differences except for Hb, RBCs, WBCs, total blood protein, and globulin which were significantly affected by the inclusion of yeast fermented PBM (P<0.05). Lysozyme activity was significantly increased in fish fed yeast fermented PBM at 5, 10, and 15 % level, while the phagocytic activity and phagocytic index were significantly increased at 20 % level when compared to the control groups (P<0.05). It is concluded from this study that inclusion of yeast fermented PBM in the diet of common carp at 15-20% level increased digestive enzyme activities, immune function and growth of the fish.

Evaluation of Yeast Fermented Poultry By-Product Meal in Nile Tilapia (Oreochromis niloticus) Feed: Effects on Growth Performance, Digestive Enzymes Activity, Innate Immunity, and Antioxidant Capacity

The aim of the present study was to examine the effects of dietary inclusion of fermented poultry by-product meal (FPBM) on growth performance, digestive enzymes activity, innate immunity, and antioxidant capacity in Nile tilapia (Oreochromis niloticus). A basal diet containing fish meal and soybean meal was considered as a control (Con), and four other diets were produced by inclusion of 10, 20, 30, or 40% FPBM (FPBM10, FPBM20, FPBM30, and FPBM40 diets). The experiment was done in triplicates (20 fish per replicate) and the fish were fed the test diets to visual satiety twice daily for 8 weeks. The groups of fish fed the FPBM10 and FPBM20 diets showed significantly (P < 0.05) higher weight gain and specific growth rate, and lower feed conversion ratio than those fed the Con and FPBM40 diets. Moreover, inclusion of 40% FPBM led to significant reduction of feed intake compared to the other treatments. FPBM at all the tested levels improved intestinal protease activity and lipase activity was enhanced at 10-30% inclusion levels. Furthermore, the FPBM10 and FPBM20 groups revealed significantly higher amylase activity than the other treatments. The FPBM10 group exhibited significantly higher phagocytic activity than the control group and phagocytic index was enhanced by dietary inclusion of 10-30% FPBM. However, inclusion of over 30% FPBM led to significant reduction of lysozyme, phagocytic, and bactericidal activities compared to the control group. Further, FPBM10 and FPBM20 diets increased the serum IgM levels, while NBT was significantly increased by feeding FPBM10 diet compared with FPBM30 and FPBM40 groups (P < 0.05). The group fed the FPBM30 diet showed significantly higher glutathione peroxidase activity than the control group. According to the analysis of the data by the polynomial regression, the inclusion of FPBM at 11.17-25.14% can be applied effectively in the diets of tilapia for better growth performance and health condition.

Bioconcentration and depuration of cadmium in the selected tissues of rare minnow (Gobiocypris rarus) and the effect of dietary mulberry leaf supplementation on depuration

A 56-day trial was conducted to elucidate the bioconcentration and depuration of Cd in the liver and muscle of rare minnow (Gobiocypris rarus) and determine the effect of dietary mulberry leaf supplementation on depuration. Juvenile rare minnow were exposed to environmentally relevant doses of Cd (1 and 10 μg/L) for 28 days of uptake and then allowed 28 days of depuration. The bioaccumulation factors of the treated rare minnow in the liver and muscle were calculated to be between 4.13-4.675 and 1.76-1.94, respectively. This results suggested that Cd had high potential for bioconcentration in rare minnow. To investigate the effect of dietary mulberry leaf supplementation on depuration, the remaining fish of each group were allowed to depurate with different ratios (0%, 10%, and 30% dry weight) of dietary mulberry leaf supplementation for an additional 28 days. Fish weights did not differ significantly (p >  0.05) between the control and mulberry leaf treated groups. Mulberry leaf powder did not significantly affect Cd depuration in the 10 μg/L group or in the muscle of the 1 μg/L group, but caused a significant decrease in Cd content in the liver of the 1 μg/L group (p <  0.05). This work was the first to model the bioconcentration of Cd in rare minnow and showed that mulberry leaf supplementation decreased Cd residues in the liver of the 1μg/L group. Such a finding may promote the development of new approaches to mitigate the potential hazards of heavy metals to human health.

Fermented mulberry leaf meal as fishmeal replacer in the formulation of feed for carp Labeo rohita and catfish Heteropneustes fossilis-optimization by mathematical programming

Search for cost-effective, eco-friendly and sustainable plant resources as potential feedstuff to replace fishmeal in the formulation of feed for fish has been in the forefront of aquaculture researches since the last few years. In this study, experiments were conducted to evaluate if replacement of fishmeal by the fermented leaf meal of mulberry (Morus indica) was viable in the formulation of feed for carp fish Labeo rohita and catfish Heteropneustes fossilis. Four iso-proteinous, iso-lipidic and iso-energetic experimental feed were formulated by replacing 0, 25, 50 and 75% of fishmeal by the fermented mulberry leaf meal (FMLM), and both species were grown on these feeds for 8 weeks. Since the results revealed differences in response to fishmeal replacement level between parameters, we determined optimum fishmeal replacement level (OFRL) for each parameter from the polynomial curve equation. While maximum weight gain and specific growth rate and minimum feed conversion ratio was found at 30-32% OFRL for L. rohita and at 52-53% OFRL for H. fossilis, other parameters responded differently in both fish. Therefore, we applied a two-phase fuzzy goal programming technique using all parameters, which showed overall OFRL for L. rohita and H. fossilis as 30.95% and 52%, respectively. We also applied the concept of 'decision tree' to identify the key factor behind utilization of FMLM. It was concluded that activity of amylase and subsequent utilization of carbohydrate was the key factor in utilizing FMLM. Interestingly, H. fossilis was found more efficient in utilizing carbohydrate of FMLM than L. rohita.

Bioprocessed poultry by-product meals on growth, gut health and fatty acid synthesis of juvenile barramundi, Lates calcarifer (Bloch)

Poultry by-product meal (PBM) has been utilised as a substitute of fishmeal (FM) in many aquaculture species. However, little information is known regarding the use of bioprocessed PBM (BPBM) in aquaculture production. This study was undertaken to investigate whether replacing FM with BPBM improved growth performance, gut morphology and fatty acid synthesis of juvenile barramundi, Lates calcarifer. The PBM was bioprocessed by baker yeast, Saccharomyces cerevisae and Lactobacillus casei. The BPBM was used to replace FM at 75% and 100% (75BPBM and 100BPBM) contrasting against unprocessed PBM (75PBM and 100PBM) at the same levels and FM based diets as the control. Juvenile barramundi with a mean initial weight of 3.78±0.16 g were stocked at a density of 20 fish per tank. After the 42 days of study, the final weight, specific growth rate and feed conversion ratios of fish fed 75PBM and 75BPBM were not significantly different from the control. However, 100% supplementation diets of 100PBM and 100BPBM resulted in reduced performance in all growth and feed variables except total feed intake and survival. The hind gut microvillus density was significantly higher (P<0.05) in fish fed 75BPBM, whereas the microvillus diameter remained unaffected with the other experimental diets when compared to the control. A reduction in eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids of fish muscles led to a lower Σn-3/Σn-6 ratio in all dietary groups when compared to the control. The percentage of Σn-3 PUFAs decreased in 100% FM replacement diets of 100PBM and 100BPBM, while Σn-6 PUFAs increased when both bioprocessed and unprocessed PBM protein was increased in the diets. Fish fed bioprocessed diets had higher fatty acid hypocholesterolemic/hypercholesterolemic ratios (HH), indicating improved suitability for human consumption.