Solid state fermentation of de-oiled rice bran: Effect on in vitro protein digestibility, fatty acid profile and anti-nutritional factors

Two-stage solid-state fermentation to increase the nutrient value of corn processing waste and explore its efficacy as a feed protein source

Corn gluten meal-corn husk mixes (CCM) are an inexpensive and readily available agricultural by-product. This study explores a novel technique by converting CCM into high-value livestock feed protein sources through fermentation with Aspergillus niger AAX and Lactobacillus fermentum LLS, aiming to sustainably meet future global protein needs. The process of fermentation significantly altered the structural composition of high molecular weight proteins, zein, and dietary fibers. This transformation resulted in a marked elevation in the concentrations of peptides, free amino acids, and polyphenols. The acidic environment produced during fermentation prevented lipid oxidation in CCM, thereby extending its storability. After fermentation, the content of anti-nutritional factors decreased, while its antioxidant capacity increased. In vitro simulated digestion suggested that fermentation improved the digestibility of CCM protein. In vivo animal experiments showed that fermented CCM (FCCM) promoted growth and gut health in chicks. This study provides new insights into the utilization of CCM.

Combined treatment of rice bran by solid-state fermentation and extrusion: Effect of processing sequence and microbial strains

Solid-state fermentation (SSF) and extrusion are effective methods to improve the nutritional and sensory quality of rice bran. The effect of the processing sequence of SSF and extrusion and microbial strains on the quality of rice bran was studied. The results showed that the first SSF followed by extrusion increased the contents of phenolic, flavonoid and γ-oryzanol, but the color changed to brown. The first extrusion followed by SSF caused damage to bioactive components and antioxidant activity, but significantly increased the content of arabinoxylans. The difference between the two processing sequences may be related to the process time and the effect of substrate on microbial induction. Aspergillus oryzae and Neurospora sitophila were suitable for increasing the bioactive components of rice bran, while Lactiplantibacillus plantarum was suitable for increasing water-extractable arabinoxylan content. Different processing sequences and microbial strains have their advantages, and these results can provide reference for rice bran processing.

Exploring community succession and metabolic changes in corn gluten meal-bran mixed wastes during fermentation

Addressing the challenge of sustainable agricultural processing waste management is crucial. Protein sources are essential for livestock farming, and one viable solution is the microbial fermentation of agricultural by-products. In this study, the microorganisms utilized for fermentation were Pichia fermentans PFZS and Limmosilactobacillus fermentum LFZS. The results demonstrated that the fermented corn gluten meal-bran mixture (FCBM) effectively degraded high molecular weight proteins, resulting in increases of approximately 23.3%, 367.6%, and 159.3% in crude protein (CP), trichloroacetic acid-soluble protein (TCA-SP), and free amino acid (FAA), respectively. Additionally, there was a significant enhancement in the content of beneficial metabolites, including total phenols, carotenoids, and microorganisms. FCBM also effectively reduced anti-nutritional factors while boosting antioxidant and anti-inflammatory substances, such as dipeptides and tripeptides. The fermentation process was marked by an increase in beneficial endophytes, which was closely correlated with the enhancement of beneficial metabolites. Overall, FCBM provides a theoretical basis for substituting traditional protein resources in animal husbandry.

Metabolomics analysis of rice fermented by medicinal fungi providing insights into the preparation of functional food

Rice, a primary staple food, may be improved in value via fermentation. Here, ten medicinal basidiomycetous fungi were separately applied for rice fermentation. After preliminary screening, Ganoderma boninense, Phylloporia pulla, Sanghuangporus sanghuang and Sanghuangporus weigelae were selected for further LC-MS based determination of the changes in metabolic profile after their fermentation with rice, and a total of 261, 296, 312, and 355 differential compounds were identified, respectively. Most of these compounds were up-regulated and involved in the metabolic pathways of amino acid metabolism, lipid metabolism, carbohydrate metabolism and the biosynthesis of other secondary metabolites. Sanghuangporus weigelae endowed the rice with the highest nutritional and bioactive values. The metabolic network of the identified differential compounds in rice fermented by S. weigelae illustrated their close relationships. In summary, this study provides insights into the preparation and application of potential functional food via the fermentation of rice with medicinal fungi.

Solid-State Fermented Plant Foods as New Protein Sources

The current animal-based production of protein-rich foods is unsustainable, especially in light of continued population growth. New alternative proteinaceous foods are therefore required. Solid-state fermented plant foods from Africa and Asia include several mold- and Bacillus-fermented foods such as tempeh, sufu, and natto. These fermentations improve the protein digestibility of the plant food materials while also creating unique textures, flavors, and taste sensations. Understanding the nature of these transformations is of crucial interest to inspire the development of new plant-protein foods. In this review, we describe the conversions taking place in the plant food matrix as a result of these solid-state fermentations. We also summarize how these (nonlactic) plant food fermentations can lead to desirable flavor properties, such as kokumi and umami sensations, and improve the protein quality by removing antinutritional factors and producing additional essential amino acids in these foods.

Complimentary effect of exogenous enzymes, essential amino acids and essential fatty acids supplemented de-oiled rice bran (DORB) based diets on hematology, liver and intestinal histoarchitecture in Labeo rohita

A 60-day feeding trial was conducted to study the hematology, liver, and intestinal histoarchitecture of Labeo rohita fed with a combination of exogenous enzymes, essential amino acids, and essential fatty acids to DORB (De-oiled rice bran) based diets. Three treatments viz., T1 [DORB + phytase and xylanase (0.01% each)], T2 [DORB + phytase (0.01%) + xylanase (0.01%) + L-lysine(1.4%) + L-methionine (0.4%) + EPA and DHA (0.5%)] and T3 [DORB + phytase (0.01%), xylanase and cellulase (0.075%) + L-lysine (1.4%) +L-methionine (0.4%) + EPA and DHA (0.5%)] were used in the present study. Serum total protein, albumin content and A/G ratio varied significantly (p < 0.05) among groups. Globulin content did not vary significantly among groups (p ≥ 0.05). The Hb content, RBC and MCV count varied significantly (p < 0.05) whereas MCH, MCHC content, WBC and lymphocyte count did not vary significantly among groups (p > 0.05). The liver and intestine examination revealed no visible alteration and showed normal histo-architecture. Based on the finding it is concluded that DORB supplemented with exogenous enzymes, essential amino acids and essential fatty acids with phytase (0.01%), xylanase and cellulase (0.075%), L-lysine (1.4%), DL-methionine (0.4%) and EPA and DHA (0.5%) improves the health of L. rohita.

The Effects of Fermented Feed on the Growth Performance, Antioxidant Activity, Immune Function, Intestinal Digestive Enzyme Activity, Morphology, and Microflora of Yellow-Feather Chickens

This experiment was conducted to investigate the effects of fermented feed on growth performance, antioxidant activity, immune function, intestinal digestive enzyme activity, morphology, and microflora of yellow-feather chickens. A total of 240 one-day-old female yellow-feathered (Hexi dwarf) chickens were randomly divided into two treatment groups, with six replicates per group and 20 chickens per replicate. The control group (CK) received a basal diet, whereas the experimental group was fed a basal diet of +2.00% fermented feed (FJ). The trial lasted for 22 days. Compared with the CK, (1) the growth performance was not affected (p > 0.05); (2) immunoglobin a, immunoglobin g, immunoglobin m, interleukin-1β, and interleukin-6 were affected (p < 0.05); (3) liver superoxide dismutase, glutathione peroxidase, and catalase were higher (p < 0.05); (4) trypsin activity in the duodenum and cecal Shannon index were increased (p < 0.05); (5) the relative abundance of Actinobacteriota in cecum was increased (p < 0.05); (6) the abundance of dominant microflora of Bacteroides as well as Clostridia UCG-014_norank were increased (p < 0.05). In summary, the fermented feed improved the growth performance, antioxidant activity, immune function, intestinal digestive enzyme activity, morphology, and microflora of yellow-feather chickens.

Compound probiotics producing cellulase could replace cellulase preparations during solid-state fermentation of millet bran

Low-value agricultural by-products can be converted into high-value biological products by fermentation with probiotic strains or by enzymatic hydrolysis. However, the high costs of enzyme preparations significantly limit their applications in fermentation. In this study, the solid-state fermentation of millet bran was performed using a cellulase preparation and compound probiotics producing cellulase (CPPC), respectively. The results showed that both factors effectively destroyed the fiber structure, reduced the crude fiber content by 23.78% and 28.32%, respectively, and significantly increased the contents of beneficial metabolites and microorganisms. Moreover, CPPC could more effectively reduce the anti-nutrient factors and increase the content of anti-inflammatory metabolites. The correlation analysis revealed that Lactiplantibacillus and Issatchenkia had synergistic growth during fermentation. Overall, these results suggested that CPPC could replace cellulase preparation and improve antioxidant properties while reducing anti-nutrient factors of millet bran, thus providing a theoretical reference for the efficient utilization of agricultural by-products.

Cereal bran proteins: recent advances in extraction, properties, and applications

The projected global population is expected to reach around 9.7 billion by 2050, indicating a greater demand for proteins in the human diet. Cereal bran proteins (CBPs) have been identified as high-quality proteins, with potential applications in both the food and pharmaceutical industries. In 2020, global cereal grain production was 2.1 billion metric tonnes, including wheat, rice, corn, millet, barley, and oats. Cereal bran, obtained through milling, made up 10-20% of total cereal grain production, varying by grain type and milling degree. In this article, the molecular composition and nutritional value of CBPs are summarized, and recent advances in their extraction and purification are discussed. The functional properties of CBPs are then reviewed, including their solubility, binding, emulsifying, foaming, gelling, and thermal properties. Finally, current challenges to the application of CBPs in foods are highlighted, such as the presence of antinutritional factors, low digestibility, and allergenicity, as well as potential strategies to improve the nutritional and functional properties by overcoming these challenges. CBPs exhibit nutritional and functional attributes that are similar to those of other widely used plant-based protein sources. Thus, CBPs have considerable potential for use as ingredients in food, pharmaceutical, and other products.

Impacts of germination and lactic acid bacteria fermentation on anti-nutrients, bioactive compounds, and selected functional properties of industrial hempseed (Cannabis sativa L.)

The impact of fermentation and germination on the metabolite profile and bioactive of 'Cheongsam' hempseed was investigated. The seeds were germinated for 3 days at 26 °C and fermented for 48 h at 37 °C using Pediococcus acidilactici (SRCM201591). The raw (R), fermented seed (RF), sprouts (S), and fermented sprouts (SF) extracts were assessed for anti-nutrients, metabolite profile, and selected bioactivities. Germination and fermentation significantly altered anti-nutrient levels (tannins, saponins, phytic acid, and trypsin inhibitors). They increased total polyphenols, flavonoid contents, and individual polyphenols and cannabinoids. SF demonstrated the highest ABTS (IC50, 291.65 µg/mL) and DPPH (IC50, 345.30 µg/mL) scavenging capacities. However, S (IC50, 73.295 µg/mL) was the most potent anti-inflammatory ingredient. SF (IC50, 74.07 µg/mL) exhibited the most potent alpha-glucosidase inhibition for enzyme inhibitions, while RF (IC50, 63.31 µg/mL) showed the best lipase inhibition potential. The findings demonstrate that germination and fermentation could improve the functional properties of hempseed.

Valorization of agro-industrial wastes into animal feed through microbial fermentation: A review of the global and Ghanaian case

Agricultural and industrial activities around the world lead to the production of large quantities of agro-industrial wastes (e.g., peels of cassava, pineapple, plantain, banana, and yam, as well as rice husks, rice bran , corn husks, corn cobs, palm kernel cake, soybean meal, wheat bran, etc.). These agro-industrial wastes are discarded indiscriminately, thereby polluting the environment and becoming hazardous to human and animal health. Solid-state fermentation (SSF), a microbial fermentation process, is a viable, efficient approach that transforms discarded agro-industrial wastes into a plethora of useful value-added bioproducts. There is growing interest in the application of SSF in valorizing agro-industrial wastes for the production of fermented, protein-rich animal feed within the livestock industry. SSF reduces anti-nutritional factors whose presence hinders the digestibility and bioavailability of nutrients in agro-industrial wastes. Thus, the application of SSF improves the nutrient contents and quality of valorized agro-industrial wastes as animal feed. Fermented animal feed production may be safer, cheaper and enhance the overall growth performance and health of animals. SSF, therefore, as a strategic approach in a circular bioeconomy, presents economic and practical advantages that guarantee efficient recycling and valorization of agro-industrial wastes that ameliorate environmental pollution. This paper reviews the status of global and local Ghanaian biotransformation and valorization of agro-industrial wastes through SSF for the production of nutrient-rich animal feed.

A review and meta-analysis of selected plant protein sources as a replacement of fishmeal in the diet of tilapias

Numerous studies on the replacement of fishmeal with plant protein sources in tilapias have been undertaken. In order to quantify the effect of replacing fishmeal with plant protein sources on the growth performance of tilapias, a meta-analysis approach was applied. Despite the high heterogeneity and funnel plot asymmetry, the meta-analysis showed that replacing fishmeal with plant protein sources has a significant positive effect on the growth performance of tilapias. Thus, tilapias appear to be preadapted to utilizing plant protein sources. Furthermore, the feed value, nutritional quality and cost of the commonly used plant ingredients (soybean, sunflower, canola, cottonseed, kikuyu and azolla meals) were explored. The Solver function in Excel was used to formulate least cost diets using the plant meals. Azolla had the highest nutritional index (9.7436). This was attributed to its excellent amino acid profile that exceeded the requirements of tilapias. Nutritional index and feed value were lowest in kikuyu because of its poor amino acid profile as it registered the lowest amino acid index (0.4918). These results indicate that the amino acid profile is more important in the determination of nutritional quality than the percent protein content. Azolla and soybean meal are good candidates for the replacement of fishmeal in the diets of tilapias.

Co-fermented defatted rice bran alters gut microbiota and improves growth performance, antioxidant capacity, immune status and intestinal permeability of finishing pigs

Based on preparation of co-fermented defatted rice bran (DFRB) using Bacillus subtilis, Saccharomyces cerevisiae, Lactobacillus plantarum and phytase, the present study aimed to evaluate the effects of co-fermented DFRB on growth performance, antioxidant capacity, immune status, gut microbiota and permeability in finishing pigs. Ninety finishing pigs (85.30 ± 0.97 kg) were randomly assigned to 3 treatments (3 replicates/treatment) with a basal diet (Ctrl), a basal diet supplemented with 10% unfermented DFRB (UFR), and a basal diet supplemented with 10% fermented DFRB (FR) for 30 d. Results revealed that the diet supplemented with FR notably (P < 0.05) improved the average daily gain (ADG), gain to feed ratio (G:F) and the digestibility of crude protein, amino acids and dietary fiber of finishing pigs compared with UFR. Additionally, FR supplementation significantly (P < 0.05) increased total antioxidant capacity, the activities of superoxide dismutase and catalase, and decreased the content of malonaldehyde in serum. Furthermore, FR remarkably (P < 0.05) increased serum levels of IgG, anti-inflammatory cytokines (IL-22 and IL-23) and reduced pro-inflammatory cytokines (TNF-α, IL-1β and INF-γ). The decrease of serum diamine oxidase activity and serum D-lactate content in the FR group (P < 0.05) suggested an improvement in intestinal permeability. Supplementation of FR also elevated the content of acetate and butyrate in feces (P < 0.05). Moreover, FR enhanced gut microbial richness and the abundance of fiber-degrading bacteria such as Clostridium butyricum and Lactobacillus amylovorus. Correlation analyses indicated dietary fiber in FR was associated with improvements in immune status, intestinal permeability and the level of butyrate-producing microbe C. butyricum, which was also verified by the in vitro fermentation analysis. These findings provided an experimental and theoretical basis for the application of fermented DFRB in finishing pigs.

Recent Developments in Fermented Cereals on Nutritional Constituents and Potential Health Benefits

Fermentation is one of the most economical and safe methods to improve the nutritional value, sensory quality and functional characteristics of raw materials, and it is also an important method for cereal processing. This paper reviews the effects of microbial fermentation on cereals, focusing on their nutritional value and health benefits, including the effects of fermentation on the protein, starch, phenolic compounds contents, and other nutrient components of cereals. The bioactive compounds produced by fermented cereals have positive effects on health regulation. Finally, the future market development of fermented cereal products is summarized and prospected.

Dynamics of defatted rice bran in physicochemical characteristics, microbiota and metabolic functions during two-stage co-fermentation

Defatted rice bran (DFRB) is an inexpensive and easily available agricultural byproduct. Existence of anti-nutritional factors (ANFs), high fiber and low protein content, susceptible to oxidation and rancidity make DFRB currently underutilized. In this study, Bacillus subtilis with high enzyme activities, Saccharomyces cerevisiae with high single-cell proteins concentration and Lactiplantibacillus plantarum with excellent acid secreting capacity were screened to co-fermented DFRB with phytase, and multiple physicochemical analyses combined with high-throughput sequencing were applied to provide insights into the dynamics of the physicochemical characteristics and the complex microbiome during the two-stage co-fermentation of DFRB. The results showed that co-fermentation effectively improved the nutritional value by degrading ANFs (trypsin inhibitors and phytic acid), fiber (acid detergent fiber and neutral detergent fiber) and allergenic protein, and increasing the trichloroacetic acid soluble protein, amino acids and organic acid. In addition, co-fermentation prevented lipid oxidation by enhancing antioxidant activity and reducing the activity of lipase and lipoxygenase. High-throughput sequencing results suggested that co-fermentation optimized microbial community of DFRB by increasing desirable Lactobacillus, Pediococcus, Saccharomyces and Talaromyces and reducing undesirable bacteria (Enterobacter and Pseudomonas) and animal and plant-pathogenic fungi (Blumeria, Alternaria, Fusarium, etc.). Furthermore, high-throughput sequencing and gas chromatography-mass spectrometry (GC-MS) were adopted to predict microbial metabolic functions and metabolic pathways during whole DFRB co-fermentation.

Solid State Fermentation as a Tool to Stabilize and Improve Nutritive Value of Fruit and Vegetable Discards: Effect on Nutritional Composition, In Vitro Ruminal Fermentation and Organic Matter Digestibility

Simple Summary

A huge quantity of fruits and vegetables are wasted every year, having a negative impact in both the economy and the environment. Valorizing them as animals’ feeds would contribute to reduce feeding cost and, at the same time, would be in the interest of prevention of resource wastage and better economy of the processing plants. The aim of this study was, on the one side, to transform fruit and vegetable discards using solid state fermentation (SSF) to a stabilized product enriched in protein and, on the other side, to evaluate its suitability for ruminants feeding by determining the in vitro organic matter digestibility, fermentation characteristics and methane production of the control and the fermented product. As a result, it was found that SSF reduced the organic matter and reducing sugar content of the fermented product, while crude protein and fiber fractions were increased. In conclusion, SSF led to a stabilized feed ingredient enriched in protein, but at the expense of digestibility reduction.

Abstract

This research aimed to evaluate in vitro organic matter digestibility, fermentation characteristics and methane production of fruit and vegetable discards processed by solid state fermentation (SSF) by Rhizopus sp. Mixtures were composed of approximately 28% citric fruits, 35% other fruits and 37% vegetables. Fruit and vegetables were processed and fermented to obtain a stabilized product. Nutritional characterization and in vitro ruminal fermentation tests were performed to determine the effect of fungal bioconversion on digestibility, end products and gas production kinetics. Results indicate that SSF reduced organic matter and reducing sugars, while it increased crude protein and neutral detergent fiber, acid detergent fiber and neutral detergent insoluble protein. The in vitro gas production showed that SSF led to a reduction of the organic matter digestibility (p < 0.001), short chain fatty acids (SCFA; p = 0.003) and CH₄ (p = 0.002). SSF reduced the gas production from the insoluble fraction (p = 0.001), without modifying the production rate (p = 0.676) or the lag time (p = 0.574). Regarding SCFA profile, SSF increased acetic (p = 0.020) and decreased propionic (p = 0.004) and butyric (p = 0.006) acids proportions, increasing acetic to propionic (p = 0.008) and acetic plus butyric to propionic (p = 0.011) ratios. SSF succeeded in obtaining a stabilized material enriched in protein, but at the expense of a reduction of protein availability and organic matter digestibility. These changes should be considered before including them in a ruminant’s rations.

Exogenous phytase and xylanase supplementation of formulated diets for rohu (Labeo rohita): impact on haematology, histology and IGF I gene expression

The present study aims to delineate the effect of exogenous enzyme supplementation of fermented or non-fermented de-oiled rice bran (DORB) on haematology, histology and expression of IGF I gene expression of Labeo rohita. Four test diets, namely, T1 (DORB), T2 (fermented DORB), T3 (DORB+exogenous enzyme) and T4 (fermented DORB+exogenous enzyme) were formulated and fed to the L. rohita for a period of 60 days. The test diets T3 and T4 were supplemented with 0.1 g kg^-1 xylanase (16,000 U kg^-1) and 0.1 g kg^-1 phytase (500 U kg^-1) enzymes. A total of 120 juveniles of L. rohita (average weight 5.01 ± 0.02 g) were stocked in 12 rectangular tanks with 10 fish per tank in triplicates. At the end of the experiment, haematology, histology and IGF I gene expression of the different groups were analysed. The haemoglobin (Hb) content, RBC count and WBC count of L. rohita varied significantly (p < 0.05) among different groups. T3 diet-fed group had the highest Hb content, RBC count and WBC count as compared to the other groups. The MCV content was significantly (p < 0.05) lower in T3 group. The DORB type, exogenous enzyme supplementation and their interaction have no significant (p > 0.05) effect on MCH, MCHC and lymphocyte content of the cultured fish. The group which were fed T3 diet had significantly (p < 0.05) higher IGF-I gene expression as compared to other groups. The histological examination of liver revealed no pathological alteration of this organ. Similarly, there were no pathological changes observed in intestinal tissue in any dietary treatment group. Based on the findings of the present study, it is concluded that exogenous enzyme supplementation of DORB-based diets improves the physiological status and growth performances of Labeo rohita.

Production and characterization of a novel, thermotolerant fungal phytase from agro-industrial byproducts for cattle feed

OBJECTIVE

The application of phytases helps in releasing bound phosphorus and other nutrients in cattle feed eventually reducing the need for supplementations. However, high production cost owing to the unavailability of cheaper sources of phytases has limited their usage in developing countries. Herein, firstly isolation, identification of a phytase from fungal isolate, Aspergillus niger NT7 was carried out followed by optimizing of all production parameters, through solid-state fermentation (SSF). Secondly, crude phytase was characterized and potential applicability of crude phytase was evaluated for dephytinization of wheat bran.

RESULTS

The highest phytase production (208.30 ± 0.22 U/gds) was achieved using wheat bran as cheap agro-industrial substrate for SSF. The various physiological parameters were optimized including inoculum age and level (3-day old inoculum and 15 × 10⁷ spores/ml), temperature (35 °C), a moistening agent (distilled water), medium pH (5), and supplementation of various biochemicals like sugar (Mannitol), nitrogen (ammonium sulphate) and detergent (Tween 80). Process optimization through one variable at a time (OVAT) approach increased the difference in productivity to more than 200%. The crude phytase of A. niger NT7 was thermostable, with optimal activity at 60 °C and also displayed optimal activity over a broad range of acidic pH. Further, enhancement in phytase activity was found specifically in the presence of Ca²⁺, Zn²⁺, and Co²⁺ ions, while other metal ions including Fe²⁺, Fe³⁺, Mn²⁺, Mg²⁺and Cu²⁺ inhibited its activity. Finally, the phytase showed efficient and sustained release of inorganic phosphate, proteins, and reducing sugars (> 60 h) from livestock feed.

CONCLUSION

Overall, our report highlights the production of an efficient and thermotolerant phytase with potential as a low-cost animal feed supplement.

Valorising Agro-industrial Wastes within the Circular Bioeconomy Concept: the Case of Defatted Rice Bran with Emphasis on Bioconversion Strategies

The numerous environmental problems caused by the extensive use of fossil resources have led to the formation of the circular bioeconomy concept. Renewable resources will constitute the cornerstone of this new, sustainable model, with biomass presenting a huge potential for the production of fuels and chemicals. In this context, waste and by-product streams from the food industry will be treated not as “wastes” but as resources. Rice production generates various by-product streams which currently are highly unexploited, leading to environmental problems especially in the countries that are the main producers. The main by-product streams include the straw, the husks, and the rice bran. Among these streams, rice bran finds applications in the food industry and cosmetics, mainly due to its high oil content. The high demand for rice bran oil generates huge amounts of defatted rice bran (DRB), the main by-product of the oil extraction process. The sustainable utilisation of this by-product has been a topic of research, either as a food additive or via its bioconversion into value-added products and chemicals. This review describes all the processes involved in the efficient bioconversion of DRB into biotechnological products. The detailed description of the production process, yields and productivities, as well as strains used for the production of bioethanol, lactic acid and biobutanol, among others, are discussed.

Physio-metabolic and haematological changes of Labeo rohita fed with graded level of de-oiled rice bran-based diet

A 60-day feeding trial was conducted with six experimental diets containing 260 g/kg crude protein and 70 g/kg lipid with varying level of de-oiled rice bran (DORB), viz., 33 (T33), 38 (T38), 43 (T43), 48 (T48), 53 (T53) and 58% (T58) to assess the digestive, metabolic and haematological responses in Labeo rohita. One hundred and eighty (180) fingerlings with ten fish per tank having an average weight of 9.8 ± 0.5 g were randomly distributed within six treatments in triplicates following a completely randomised design. The amylase and lipase activities in the whole intestine did not vary significantly (P > 0.05), but protease activity varied significantly with respect to DORB level in the diet. At higher (53 and 58%) inclusion level of DORB, the protease activities were lower. T33, T38 and T43 groups showed significantly (P < 0.05) higher aspartate aminotransferase (AST) activity compared to the other groups, whereas lowest activity was recorded in the group fed with highest inclusion level (58%). The oxidative stress enzyme like superoxide dismutase (SOD), catalase and glutathione-S-transferase exhibited significantly higher activities in liver of T58 group of L. rohita. However, the activity of catalase and SOD showed no significant variation in gill tissue. The haematological parameter values such as red blood cell (RBC), white blood cell (WBC), haemoglobin (Hb) and packed cell volume (PCV) were lower in the highest DORB fed group (T58) as compared to their lower DORB inclusion counterparts. No change in NBT value was recorded irrespective of DORB inclusion level in the diet. Hence, from these results, it can be concluded that the dietary inclusion of DORB up to 43% in the diet of L. rohita at 26% crude protein and 7% lipid level is best for the optimal activity of digestive, metabolic and haematological parameters.