Dietary Chitin Research Articles

Changes in the physiology and chitin metabolism in cultured juvenile Panulirus ornatus across the moult cycle

Crustaceans undergo periodic moulting events to facilitate growth, this is a physiological and energetically demanding process. In an aquaculture environment, crustaceans are generally cultured in a defined space and often at high densities, where exposure to cannibalism may be greater than in the wild. Panulirus ornatus is one such emerging aquaculture candidates, moulting frequently as juveniles and providing the opportunity to investigate the relationship between physiology and genetics throughout this important developmental period. In this study, P. ornatus juveniles were assessed every three days across the seventh to eighth juvenile moult phase, sampling was divided into six distinct time points. Brix index, hepatosomatic index, and circulating ecdysone concentrations were measured across these time points. The Brix index was validated as a useful tool for assessing the moult-stages of juvenile P. ornatus, with an increase in Brix value seen in the lead up to ecdysis. Chitin metabolism was mapped, with Chitinase 3 demonstrating hepatopancreas specificity, indicating a role outside of breakdown of dietary chitin. The investigation of physiological parameters across a moult cycle provides a basis for improving moult cycle staging in cultured P. ornatus juveniles and provides further characterisation of the changes that occur during moulting in this species.

Growth performance, hepatic gene expression, and plasma biochemistry of rainbow trout fed full-fat meal, defatted meal, oil and chitin from black soldier flies

Insects, such as black soldier flies (BSF), are sustainable alternatives to fishmeal and fish oil that have been shown maintain fish growth performance, especially at low dietary inclusions. However, BSF is commonly processed to remove chitin and oil that may have additional benefits to the immune response and disease resistance of fish. The aim of this study was to investigate the hepatic gene expression and plasma biochemistry of rainbow trout (Oncorhynchus mykiss) fed BSF meals and BSF components. A three-month feeding trial was performed where rainbow trout (90.0 ± 4.0g; mean ± SD) were fed either a control diet or diets that contained: 10 % full-fat BSF, 10 % defatted BSF, 4 % BSF oil, and 1 % BSF chitin. Liver was analyzed for gene expression via qPCR and plasma was analyzed for 21 biochemical markers. The 4 % oil and 1 % chitin diets had the highest effect on growth performance, i.e. final weight (p=0.043) and feed intake (p=0.017), compared to the control diet, while no effects of these diets were found on hepatic gene expression. The 10 % full-fat BSF diet affected gene expression, specifically upregulating the pro-inflammatory cytokine IL-8 (p=0.033), which may be due to the higher content of saturated fatty acids (SFA) and subsequently immune cell activity in the fish or the combination of the SFA and antimicrobial peptides in BSF that stimulate the innate immune system. No other immune and oxidative stress genes, or 21 plasma biochemical markers were found to be significantly affected (p>0.05). This research provides support to include and not remove oil and chitin from BSF since these components can improve growth performance and immune response of rainbow trout.

207 Impacts of beak trimming and dietary fiber on welfare and productivity of laying hens

Abstract Beak trimming is a routine management practice in the egg industry to reduce damage caused by injurious pecking; however, it raises welfare concerns including pain and sensory loss. Dietary manipulation may be a feasible and welfare-friendly alternative to beak trimming in laying hens. Here, we hypothesized that dietary inclusion of insoluble fiber (chitin) throughout the starter and grower periods would result in improved welfare and productivity in both beak-trimmed and beak-intact chickens. One-day old female Hy-Line Browns (n = 192) were randomly assigned to one of four treatments in a 2 X 2 factorial design (n = 4 pens/treatment; 12 birds/pen): birds were infrared beak-trimmed or had their beaks left intact and were fed one of two diets (standard vs. 2% chitin) for 8 wk. Birds were housed in floor pens containing litter and perches with ad libitum access to feed and water. Body weight and feed intake were recorded weekly. Beak sensitivity was assessed using a pressure transducer to measure pecking force weekly from 3 to 8 wk of age. A tonic immobility test was performed at 7 wk of age to measure fearfulness. Plasma corticosterone was determined using enzyme-immunoassay procedures at 8 wk of age. Data were analyzed with linear mixed models with beak condition and dietary treatment modeled as fixed effects, and pen and bird ID as random effects. Beak-trimmed birds fed the standard diet weighed less (P < 0.001) than all other groups throughout all growth stages, including starter 1 (0-3 wk), starter 2 (4 to 6 wk), and grower (7 to 8 wk; Table 1). Beak-intact birds fed 2% chitin had a greater feed intake and feed conversion ratio (P < 0.05) compared with other groups during the starter 2 and overall experimental period. Beak-trimmed birds exhibited weaker pecking force than beak-intact birds for the first 7 wk (P < 0.001; Table 2). Beak-trimmed birds fed 2% chitin had significantly less corticosterone (Figure 1) than birds fed the standard diet (P < 0.05), and a shorter tonic immobility duration than all other groups (P < 0.05). Dietary chitin was also associated with a shorter latency until the first alert head movement and a greater number of inductions of tonic immobility than the standard diet (P < 0.05), which suggests that insoluble fiber supplementation reduces fearfulness regardless of beak-condition status. Our results suggest infrared beak trimming increases beak sensitivity for several weeks, potentially resulting in decreased feed intake and body weight in the first 8 wk of life (Table 3). Dietary supplementation with chitin appears to offset the effects of beak trimming on growth, but not beak sensitivity, and may improve welfare in beak-trimmed and beak-intact birds by reducing stress responses. Future studies are needed to elucidate the different mechanisms behind the observed effects.

Live yellow mealworm (Tenebrio molitor) larvae: a promising nutritional enrichment for laying quails

The study aimed to evaluate the effect of supplementing live Tenebrio molitor (TM) larvae to laying quails (Coturnix japonica) as nutritional enrichment. Live performances, apparent digestibility of nutrients (including that of sole live TM larvae), egg physicochemical quality, sensory traits, and storage stability were considered in this experiment. Sixty laying quails were divided into 2 dietary groups (6 replicated cages/group; 5 quails/cage): a Control group received a basal diet for laying quails and a TM10 group was fed with the Control diet supplemented with live TM larvae (10% of the expected daily feed intake). For the digestibility trial, 30 laying quails were divided into 3 dietary groups: the first 2 groups were fed with the Control and TM10 diets, while the third group received ad libitum live TM larvae (TM100) as a complete replacement for the Control diet. Overall, no mortality was recorded during the trials. Quails fed TM showed a remarkable capability of digesting dietary chitin (P < 0.0001). TM100 quails showed the lowest digestibility for dry matter, crude protein, and energy, but that of ether extract was the highest (P < 0.001). The presence of live TM larvae stimulated quails' feed intake (P < 0.0001), but did not affect performance traits. Similarly, overall physicochemical quality attributes and storage stability were comparable in Control and TM10 eggs. The sensory features of quail eggs differed in TM10 vs. Control groups: TM10 eggs had the lowest overall flavor (P < 0.01), sulfur (P < 0.05) and greasy-oily (P < 0.01) intensities. Therefore, a 10% TM dietary supplementation is effective in stimulating feeding activity of quails, but it did not provide any productive improvement compared to a standard diet. Further studies should assess the possible beneficial effect of live TM supplementation on quail's gut health. The digestibility trial with the sole live TM larvae allowed to assess the specific nutritional value of this emerging feedstuff which is of utmost importance for future feed formulations.

A type 2 immune circuit in the stomach controls mammalian adaptation to dietary chitin.

Dietary fiber improves metabolic health, but host-encoded mechanisms for digesting fibrous polysaccharides are unclear. In this work, we describe a mammalian adaptation to dietary chitin that is coordinated by gastric innate immune activation and acidic mammalian chitinase (AMCase). Chitin consumption causes gastric distension and cytokine production by stomach tuft cells and group 2 innate lymphoid cells (ILC2s) in mice, which drives the expansion of AMCase-expressing zymogenic chief cells that facilitate chitin digestion. Although chitin influences gut microbial composition, ILC2-mediated tissue adaptation and gastrointestinal responses are preserved in germ-free mice. In the absence of AMCase, sustained chitin intake leads to heightened basal type 2 immunity, reduced adiposity, and resistance to obesity. These data define an endogenous metabolic circuit that enables nutrient extraction from an insoluble dietary constituent by enhancing digestive function.

Potential of shrimp waste meal and insect exuviae as sustainable sources of chitin for fish feeds

Aquaculture is one of the world's fastest growing food-producing sectors, providing more than half of all fish consumed globally for human nutrition. However, to maintain such growth and meet the increasing demand for aquatic food, sustainable raw materials for fish feeds are needed. In this regard, insects represent one of the most promising alternatives to fish meal (FM) protein source for use in aquafeeds. In addition to protein, insects contain bioactive compounds, such as chitin, which is a natural polysaccharide abundantly present in the pupal exuviae of some insects. Studies have shown that dietary chitin or its derivate chitosan acts as a prebiotic thus modulating the gut microbial communities of fish. Accordingly, the present study aimed to evaluate the effect of two waste products rich in chitin, i.e., shrimp head meal (SHM), and insect (Hermetia illucens) pupal exuviae on the gut microbiota of rainbow trout (Oncorhynchus mykiss). Three isoproteic, isolipidic, and isoenergetic diets containing either FM, SHD, or a combination of FM and 1.6% of pupal exuviae meal (PEM) were tested through a 91-day feeding trial. At the end of the experiment, no differences in final mean body weight, specific growth rate, and feed conversion ratio values were observed between fish experimental groups. Mortality was <1% and it did not correlate with diet for the entire duration of the trial. However, a modulatory effect of dietary pupal exuviae on fish gut microbiota was detected. Indeed, gut bacterial species richness improved by including insect exuviae. In particular, Firmicutes and Actinobacteria phyla, mainly represented by Bacillus, Facklamia, Brevibacterium, and Corynebacterium genera, were enriched in trout receiving pupal exuviae. These genera are chitinolytic and short-chain fatty acids (SCFAs)-producing bacteria. SCFAs production was confirmed by gas chromatography analysis, which detected the highest amount of butyrate in feces of trout fed with pupal exuviae meal. Functional inference analysis of intestinal microbiota using PICRUST metagenome prediction tool, showed differences in response to diet. In particular, eleven pathways were significantly different between control fish (FM) and fish fed the PEM diet, whereas twenty functional traits were significantly different between the FM and SHM fish groups. Overall, our data confirmed that chitin from insect's pupal exuviae represents a promising functional ingredient, better than SHM, for positively modulating gut microbiota communities of rainbow trout.

Chitin digestibility and intestinal exochitinase activity in Nile tilapia and rainbow trout fed different black soldier fly larvae meal size fractions

Black soldier fly (Hermetia illucens) larvae meal (BSFLM) is a novel fish feed ingredient with a high crude protein content (~40% dry matter, DM). However, BSFLM also contains chitin, which might impair nutrient digestibility. To investigate the effect of chitin on nutrient digestibility and chitinase activity in fish, BSFLM with different chitin contents were tested as feed ingredients for Nile tilapia (Oreochromis niloticus) and rainbow trout (Oncorhynchus mykiss). BSFLM was sieved into three size fractions obtaining different chitin contents: 0–200 μm (fine), 200–400 μm (medium), >400 μm (coarse), 1.8, 2.7 and 15.4% chitin on a DM basis, respectively. Four isoenergetic and isonitrogenous diets were formulated for each species including an experimental reference diet and three diets replacing 25% of the experimental reference diet matrix with one of the three BSFLM size fractions. Dietary inclusion of the coarse BSFLM fraction resulted in significantly lower apparent digestibility of DM, crude protein, nitrogen-free extract and chitin when compared with the other treatment groups in both fish species, which supports the hypothesis that chitin might act as an anti-nutrient. However, it was also found that both species could digest chitin but its digestibility decreased with a higher dietary chitin inclusion level. Furthermore, β-N-acetylglucosaminidase activity (exochitinase) increased with higher dietary chitin inclusion in the proximal and distal intestine of both fish species suggesting that exochitinase production can be upregulated depending on the dietary chitin intake. Overall, the results corroborate that chitin could act as a nutrient source as well as an anti-nutrient in both Nile tilapia and rainbow trout.

Making a meal out of bugs

Making a meal out of bugs

Effects of chitin from Daphnia similis and its derivative, chitosan on the immune response and disease resistance of white shrimp, Litopenaeus vannamei

Daphnia similis chitin and its derivative chitosan were prepared as immunostimulants to boost the immune response and determine the ability to control infectious disease caused by Vibrio alginolyticus in white shrimp, Litopenaeus vannamei. Three experimental diets supplemented with 0% chitin or chitosan (control) and 0.4% chitin or 0.4% chitosan were fed to shrimp for 56 days. Dietary inclusion of 0.4% chitosan accelerated shrimp growth compared to chitin and control. The survival and disease resistance of shrimp increased significantly when fed chitin and chitosan diets, after pathogenic injection, as indicated by the up-regulated immune responses in respiratory burst (RB), superoxide dismutase (SOD), and phagocytic activity (PA). There were no significant differences in the total haemocyte count (THC), phenoloxidase (PO)activity, and lysozyme (LYZ) activity among the groups. No significant differences were observed for prophenoloxidase system-related gene expressions among groups. However, shrimp fed chitin, and chitosan expressed significantly higher levels of antimicrobial proteins (penaeidin 3a, crustin, and anti-lipopolysaccharide factor 2) in the haemocytes than in control. The gene expressions of catalase and heat shock protein 70 increased in the hepatopancreas of shrimp fed chitosan diet compared to the chitin and control diet. The O-linked N-acetylglucosamine transferase (ogt) was significantly higher in the haemocytes of shrimp fed chitosan and chitin than the control, but ogt was only significantly higher in the hepatopancreas of shrimp fed chitosan. Dietary chitin and chitosan also showed positive effects on the transcription of peritrophin-like protein. These findings suggest that both chitin and chitosan from D. similis are efficacious at boosting the immunity of shrimp by preventing and controlling infectious diseases caused by Vibrio and have great potential to be used as a feasible immunostimulant that significantly contributes to the circular economy.

Characterization and functional analysis of a chitinase gene: Evidence of Ch-chit participates in the regulation of biomineralization in Crassostrea hongkongensis

Chitinase is a key enzyme in many organisms that functions as a defense against chitin-coated pathogens or as a digestive enzyme to hydrolyze dietary chitin. Chitin is also essential for the formation of organic frameworks, involves in various biological processes, including shell formation. However, the function of chitinase of Crassostrea hongkongensis has not yet been determined. In this study, we obtained a full Ch-chit sequence from C. hongkongensis. The full length of Ch-chit cDNA encoded a predicted 470-amino acid protein, contained a signal peptide, a Glyco 18 domain, a low complexity domain, and a transmembrane domain. Phylogenetic analysis showed that Ch-chit clustered with Chit3-lp of other bivalves. In different stages of larvae development, the expression of Ch-chit in the trochophore larvae was the highest and was significantly higher than that in other stages (P < 0.05). In addition, Ch-chit gene was expressed in a variety of tissues, and its expression in mantle and digestive gland was significantly higher than that in other tissues (P < 0.05). In situ hybridization demonstrated that Ch-chit gene was mainly distributed at the edge of mantle, especially in the inner fold. Shell damage experiment revealed that the expression of Ch-chit was significantly up regulated at 6 h and peak at 12 h after shell damage (P < 0.05). When the expression of Ch-chit was interfered by RNA interference (RNAi), abnormal growth occurred on the inner surface of the prismatic layer. The above results imply that Ch-chit is involved in the shell formation, and also provide an important clue for the study of the molecular mechanism of biomineralization in C. hongkongensis.

Impacts of insect consumption on human health

Edible insects represent an understudied food resource that may promote human health. They characteristically contain ample protein, healthy fatty acids, minerals, and vitamins, and have been touted for their environmental benefits given their efficient resource use. While numerous in vitro, animal, and nutrient quantification studies have elucidated a framework of potential health impacts of entomophagy, few have measured direct health outcomes. This review investigates and summarises existing evidence on health impacts derived exclusively from human interventions. A systematic literature search was conducted in three databases: SCOPUS, Web of Science, and PubMed. Out of 1,691 initial results, only nine studies met the inclusion criteria. In these limited studies, insects were shown to have potential to: (1) promote growth and influence iron status when added to complementary foods; (2) modulate gut microbiota with some prebiotic effects; and (3) provide amino acids similar to soya protein. One study also provided isolated evidence that an insect-herb mixture could possibly reduce symptoms of chronic obstructive pulmonary disease when added to routine treatment. Importantly, results reveal a significant lack of human subjects research directly measuring health outcomes from insect consumption. Findings from the included studies indicate that insects are generally safe and offer both beneficial and neutral outcomes compared to other foods. These discoveries, in tandem with extensive evidence from non-human studies, support claims that insect consumption could further enhance health by addressing micronutrient deficiencies or promoting gut health. There are also other plausible health promoting properties of insects that could help ameliorate complications with hypertension and other non-communicable disease. More rigorous and better controlled human intervention trials are fundamental to confirm health benefits and better assess risks associated with entomophagy, while also addressing unanswered questions regarding nutrient bioavailability, the fate of dietary chitin, and in vivo activity of bioactive peptides.

Preparation of Nano/Submicron Ganoderma Tsugae and Its Stability

The preparation and stability of nano/submicrometer-sized Ganoderma tsugae (G. tsugae) was explored. The fruit body of G. tsugae was treated by homogenization and media-milling. Three sizes (0.8, 0.3, and 0.2 mm) of media were employed for consecutive milling. The final product was obtained by centrifugation (10,000 g, 10 min). Particle sizes were determined by using a laser-light particle size analyzer and further examined by using transmission electron microscopy. The removal of large particles resulted in better stability. After being stored at25°C for 21 days, the volume-average diameter of supernatant III increased from 0.105 to 0.137 μm. Freeze-drying resulted in particle aggregation and an increase in particle size. Twenty percent of the particles in the freeze-dried supernatant III were smaller than 100 nm, with an average diameter greater than 1 μm. Nevertheless, autoclaving did not result in severe instability of supernatant III. After being stored at 25°C for 12 months, about 40% of the particles were smaller than 100 nm, with an average diameter of 373 nm. In addition, the contents of bioactive compounds such as β-(1,3)-D-glucans, crude triterpenoids, total dietary fiber and chitin in media-milled products were much greater than those present in the hot-water extract.

The Changes in the Frog Gut Microbiome and Its Putative Oxygen-Related Phenotypes Accompanying the Development of Gastrointestinal Complexity and Dietary Shift.

There are many examples of symbiotic and reciprocal relationships in ecological systems; animal gut microbiome–host interactions are one such kind of bidirectional and complex relationship. Here, we utilized several approaches (16S rRNA gene sequencing, metagenomics, and transcriptomics) to explore potential gut microbiome–host interactions accompanying the development of gastrointestinal complexity and a dietary shift from metamorphosis to maturity in ornamented pygmy frogs (Microhyla fissipes). We identified the possible coevolution between a particular gut microbial group (increased putative fat-digesting Erysipelotrichaceae and chitin-digesting Bacteroides and Ruminococcaceae) and the host dietary shift [from herbivore to insectivore (high proportion of dietary chitin and fat)] during metamorphosis. We also found that the remodeling and complexity of the gastrointestinal system during metamorphosis might have a profound effect on the gut microbial community (decreasing facultative anaerobic Proteobacteria and increasing anaerobic Firmicutes) and its putative oxygen-related phenotypes. Moreover, a high proportion of chitin-digesting bacteria and increased carbohydrate metabolism by gut microbiomes at the climax of metamorphosis would help the frog’s nutrition and energy needs during metamorphosis and development. Considering the increased expression of particular host genes (e.g., chitinase) in juvenile frogs, we speculate that host plays an important role in amphibian metamorphosis, and their symbiotic gut microbiome may help in this process by providing the nutrition and energy needs. We provide this basic information for the amphibian conservation and managements.

Effects of chitin and chitosan from cricket and shrimp on growth and carcass performance of broiler chickens.

Majority of the studies on the effect of chitin and chitosan on growth and carcass characteristics of broiler chickens has concentrated more on shrimp chitin and shrimp chitosan, and often with contradictory results. Therefore, the objective of this present study is to evaluate and compare the effect of dietary chitin and chitosan from cricket and shrimp on growth performance, carcass, and organ characteristics of broiler chickens. One hundred fifty-day-old male Cobb500 broiler chicks of similar average weight were randomly allotted into one of the five dietary treatments with three replicates. Treatment 1 (T1) chicks were fed basal diet only (control), treatment 2 and 3 (T2 and T3) chicks were given basal diet with 0.5g/kg diet of cricket chitin and cricket chitosan, respectively, while treatment 4 and 5 (T4 and T5) chicks were served basal diet with 0.5g/kg diet of shrimp chitin and shrimp chitosan respectively. No significant variation occurred between cricket chitin and shrimp chitin, although data on growth performance were higher in cricket chitin, but growth performance varied significantly between cricket chitosan and shrimp chitosan. This study revealed that cricket chitin at 0.5g/kg significantly improved growth performance, carcass quality, and organ characteristics of broilers more than chitosan. Birds fed basal diet alone, although gained more weight, also accumulated more fat having the poorest feed conversion ratio (FCR) and the highest mortality. However, carcass of birds fed cricket chitin was the leanest and thus economically beneficial as they consumed the least amount of feed with the best FCR.

Dietary Chitin Particles Called Mimetic Fungi Ameliorate Colitis in Toll-Like Receptor 2/CD14- and Sex-Dependent Manners.

Chitin is a natural N-acetylglucosamine polymer and a major structural component of fungal cell walls. Dietary chitin is mucoadhesive; anti-inflammatory effects of chitin microparticles (CMPs; 1- to 10-μm diameters) have been demonstrated in models of inflammatory bowel disease (IBD). The goals of this study were to assess (i) whether CMPs among various chitin preparations are the most effective against colitis in male and female mice and (ii) whether host chitin-binding Toll-like receptor 2 (TLR2) and CD14 are required for the anti-inflammatory effect of chitin. We found that colitis in male mice was ameliorated by CMPs and large chitin beads (LCBs; 40 to 70 μm) but not by chitosan (deacetylated chitin) microparticles, oligosaccharide chitin, or glucosamine. In fact, LCBs were more effective than CMPs. In female colitis, on the other hand, CMPs and LCBs were equally and highly effective. Neither sex of TLR2-deficient mice showed anti-inflammatory effects when treated with LCBs. No anti-inflammatory effect of LCBs was seen in either CD14-deficient males or females. Furthermore, an in vitro study indicated that when LCBs and CMPs were digested with stomach acidic mammalian chitinase (AMC), their size-dependent macrophage activations were modified, at least in part, suggesting reduced particle sizes of dietary chitin in the stomach. Interestingly, stomach AMC activity was greater in males than females. Our results indicated that dietary LCBs were the most effective preparation for treating colitis in both sexes; these anti-inflammatory effects of LCBs were dependent on host TLR2 and CD14.

High-throughput sequencing of gut microbiota in rainbow trout (Oncorhynchus mykiss) fed larval and pre-pupae stages of black soldier fly (Hermetia illucens)

Black soldier fly (Hermetia illucens) meal is a potential alternative to fishmeal and plant proteins in diets for farmed fish since it can be produced on organic waste substrates, requires little energy and water inputs and contains high levels of essential amino acids. Recent studies have partially replaced fishmeal with black soldier fly meal, however, research on their impact on gut microbiota of fish is limited. In a five week experiment, juvenile rainbow trout (Oncorhynchus mykiss) were fed either a reference diet based on fishmeal or three diets with 30% inclusion of black soldier fly meals in the form of pre-pupae, larvae or defatted-larvae. The combined luminal content and mucosa were collected from the distal intestine of three fish per tank with four tanks per diet (n = 12) and 16S rRNA gene amplicons were sequenced using the Illumina MiSeq platform. Feeding the insect-based diets increased the alpha-diversity of bacteria and abundance of lactic acid bacteria, which may be due to the addition of dietary chitin. Compared with fishmeal, feeding insects resulted in higher abundance of phyla Firmicutes and Actinobacteria with lower abundance of Proteobacteria. Fish fed the full-fat meals had higher abundance of Corynebacterium that was attributed to its ability to produce lipase and the high content of dietary lipids as a substrate. Bacillaceae was increased in fish fed both larvae diets and unchanged in the pre-pupae diet, which indicated that life-cycle stage of the insect influenced the gut microbiota. Based on these results, we found that feeding black soldier flies increased diversity and altered the composition of gut bacteria of rainbow trout, which were further influenced by life-cycle stage and lipid content of the insect meal.

Gut health and serum growth hormone levels of broiler chickens fed dietary chitin and chitosan from cricket and shrimp.

ABSTRACTGrowth hormones (GH) alone does not explain the growth rate in the chicken as growth in an animal is multi-factorial. Normal morphology of the intestinal villus and crypt, with adequate regulation of intestinal nutrient transporters, is essential to a healthy gut. Nutrition plays a significant role in gut health management, but information on the effect of dietary chitin and chitosan on gut morphology, gene expression of nutrient transporter, and serum levels of GH in broiler chickens is scanty. Thus, this study aimed at evaluating the comparative effect of dietary chitin and chitosan from cricket and shrimp on the small intestinal morphology, relative gene expression of intestinal nutrient transporters and serum level of GH in the broiler. A total of 150 day-old male Cobb500 broiler chicks were randomly allotted to one of the five treatment groups (n = 30). Treatment 1 was fed basal diet only, treatments 2 to 5 were fed a basal diet with 0.5 g cricket chitin, cricket chitosan, shrimp chitin, and shrimp chitosan, respectively, per kg diet. At days 21 and 42, duodenal and jejunal samples were assessed for structural morphology and jejunum for the relative gene expression of PepT1, EAAT3, SGLT1, and SGLT5 using quantitative real-time PCR. Results bared that dietary cricket chitosan and shrimp chitosan significantly (P < 0.05) improved jejunal villus height and reduced crypt depth without improving the body weight (BW). The gut morphology of birds under cricket chitin was poor and significantly (P < 0.05) different from other treated groups. Both the dietary chitin and chitosan at day 21 and only dietary chitosan at day 42 significantly (P < 0.05) down-regulated the relative mRNA expression of PepT1, EAAT3, SGLT1, and SGLT5 of broiler chickens. Treated groups differ non-significantly at both phases, while cricket chitin numerically increased the relative expression of PepT1, EAAT3, and SGLT1. Therefore, the potential of cricket chitin to improve BW and to up-regulate nutrient transporters is worthy of further exploration.

Chitin modulates immunity and resistance of Labeo rohita (Hamilton, 1822) against gill monogeneans

The present study was conducted to delineate the effects of dietary chitin on the immune status and resistance of rohu (Labeo rohita) against gill monogeneans. The study consisted of two experimental trials. In trial-I, chitin (0.5%, 1% and 2%) was incorporated into the control diet (0% chitin) and fed to rohu (15.43 ± 0.79 g) for three weeks. The superoxide anion production, total protein content, myeloperoxidase and alkaline phosphatase activity were measured at weekly intervals. The best stimulatory dose and duration was found to be 1% chitin for 2 weeks based on the observed responses. In trial-II, a new batch of rohu (17.13 ± 1.39 g) were randomly divided into three experimental groups as follows: Negative control (‘nc’) - fish were fed with the control diet but not exposed to monogeneans; Positive control (‘pc’) – fish were fed with the control diet and exposed to monogeneans; and fish under chitin supplemented diet (‘csd’) - fish were fed with 1% chitin and exposed to monogeneans. After two weeks of feeding, infection with gill monogeneans was performed in the ‘pc’ and ‘csd’ groups by cohabitation. The experiment was continued for one more month. Various immunological parameters and parasite intensity were measured on 0, 15th and 30th-day post-challenge. The results showed significant enhancement in superoxide anion production, myeloperoxidase and total protein content of fish in the ‘csd’ group compared to the ‘nc’ group. However, no significant enhancement was observed in alkaline phosphatase, anti-protease and lysozyme activity. The mean intensity of gill monogeneans was significantly less in the ‘csd’ compared to the ‘pc’ group. In conclusion, dietary chitin showed immunostimulatory potential in rohu, predominantly at 1% inclusion level. Further, resistance against gill monogeneans was augmented in rohu following feeding with chitin.

Effect of dietary chitin on digestive enzyme activity, growth and survival of Macrobrachium tenellum juvenile prawns

Macrobrachium tenellum is a freshwater prawn native from Mexico to Peru, with potential for cultivation. Currently, it is extensively exploited by local fisheries. To understand its chitin requirements, a formulated diet with chitin added (5, 10 15, 20, and 25%) was given to juveniles for 60 days. Growth, survival, and enzyme activity (trypsin, chymotrypsin, lipase, amylase, and chitinase) were measured every 15 days. Highest final weight and specific growth rate resulted from diets with 20% chitin. Poorest performance resulted from diets with 5 and 10% chitin. Chitin in the diet did not have a significant effect on survival. Statistically significant differences in enzyme activity were not found in any treatment. Normal 0 21 false false false EN-US X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:Tabla normal; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:Times New Roman,serif;}

In Vitro and Dietary Effects of Chitin on Cellular and Humoral Immune Parameters of Catla, Catla catla (Hamilton)

AbstractImmunostimulants increase the immunocompetency and disease resistance of fish by enhancing immune responses. This study determined the in vitro and dietary effects of chitin on immune responses of catla, Catla catla. Catla head‐kidney leukocytes were cultured in complete RPMI‐1640 medium containing 0.01, 0.1, and 1.0 mg/mL of chitin. Leucocyte viability and different cellular immune responses, namely, respiratory burst, nitric oxide production, and leucocyte peroxidase content were analyzed in vitro. In the dietary experiment, chitin‐supplemented diets (0.5, 1.0, and 2.0% of feed) were fed to catla for 2 wk, and respiratory burst, serum lysozyme, and total protein contents were measured after 1 and 2 wk of feeding. Leucocytes incubated in vitro with chitin for 72 h maintained their viability. Chitin significantly (P &lt; 0.05) enhanced all the immune responses in vitro. The lowest dose showed the best response. Dietary chitin also significantly stimulated all the immune parameters in a dose‐dependent manner with the highest dose showing the maximum responses. All the responses were higher after 1 wk of feeding and declined thereafter. The results suggest that chitin stimulates catla cellular and humoral immune responses in vitro and in vivo.