Effects of Dietary Phospholipids on Growth Performance, Digestive Enzymes Activity and Intestinal Health of Largemouth Bass (Micropterus salmoides) Larvae

While the beneficial roles of dietary phospholipids on health status and overall performances of fish larvae have been well demonstrated, the underlying mechanisms remain unclear. To address this gap, the present study was conducted to investigate the effects of dietary phospholipids on growth performance, intestinal development, immune response and microbiota of larval largemouth bass (Micropterus salmoides). Five isonitrogenous and isolipidic micro-diets were formulated to contain graded inclusion levels of phospholipids (1.69, 3.11, 5.23, 7.43 and 9.29%). Results showed that the supplementation of dietary phospholipids linearly improved the growth performance of largemouth bass larvae. The inclusion of dietary phospholipids increased the activity of digestive enzymes, such as lipase, trypsin and alkaline phosphatase, and promoted the expression of tight junction proteins including ZO-1, claudin-4 and claudin-5. Additionally, dietary phospholipids inclusion alleviated the accumulation of intestinal triacylglycerols, and further elevated the activity of lysozyme. Dietary phospholipids inhibited the transcription of some pro-inflammatory cytokines, including il-1β, and tnf-α, but promoted the expression of anti-inflammatory cytokines tgf-β, with these modifications being suggested to be mediated by the p38MAPK/Nf-κB pathway. The analysis of bacterial 16S rRNA V3-4 region indicated that the intestinal microbiota profile was significantly altered at the genus level with dietary phospholipids inclusion, including a decreased richness of pathogenic bacteria genera Klebsiella in larval intestine. In summary, it was showed that largemouth bass larvae have a specific requirement for dietary phospholipids, and this study provided novel insights on how dietary phospholipids supplementation contributes to improving the growth performance, digestive tract development and intestinal health.

The Optimized Inclusion Level of Bacillus Subtilis Fermented Azolla Pinnata In Nile Tilapia (Oreochromis Niloticus) Diets: Immunity, Antioxidative Status, Intestinal Digestive Enzymes and Histomorphometry, And Disease Resistance

A 95-day feeding trial was conducted to evaluate the outcomes of feeding Bacillus subtilis fermented Azolla (BSFA) on nonspecific immunity, antioxidative status, intestinal digestive enzymes and histomorphometry, and disease resistance in the Nile tilapia. We formulated five isonitrogenous and isocaloric experimental diets to incorporate BSFA at (0%, 15%, 30%, 45%, 60%). The growth performance parameters (FBW, BWG, SGR, PER and FCR) revealed a significant increase in the BSFA30 tilapia group compared to the control group followed by BSFA45 (P < 0.05). The BSFA30 group exhibited the highest nonspecific immunity parameters (lysozyme activity, phagocytic index and phagocytic activity) compared to other groups (P < 0.05). SOD and GPx reported the highest values in the BSFA60 group. Nile tilapia carcass composition was not influenced by BSFA inclusion level (P ˃ 0.05). Interestingly, Nile tilapia fed with BSFA15 diet exhibited the highest protease activity level (P ˂ 0.05), while those fed on BSFA30 documented the highest amylase activity. Intestinal histomorphology was significantly enhanced with the gradual increase of administrated BSFA. Tilapia disease resistance against A. septicemia, BSFA significantly diminished the cumulative mortality compared to the control group. To sum up, BSFA was more effective in improving the growth performance and immunity of Nile tilapia.

Increase in body weight and protein retention on meat chicken due to the addition of probiotics and digestive enzymes in fermented diet containing maggot flour and local materials

The purpose of this study was to determine the growth response of meat chickens due to the addition of probiotics and digestive enzymes in the fermented diet containing maggot flour and local materials. The research was carried out at Field Laboratory of Animal Science, University of Syiah Kuala-Banda Aceh, Indonesia for 66 days. A total of 100 meat chickens were designed using a completely randomized design (CRD) consisting of 5 treatments, namely P0 = 100% fermented ration (control), P1 = 0.5% probiotic + 0% digestive enzymes + 100% fermented diet, P2 = 0% probiotic + 0.5% digestive enzymes + 100% fermented diet, P3 = 0.5% probiotic + 1% digestive enzymes + 100% fermented diet, P4 = 1% probiotic + 0.5% digestive enzymes + 100% fermented diet with 4 replications. The data obtained were analyzed using ANOVA (Analysis of variance) and significant difference of data was analyzed by Duncan’s multiple distance test. The results showed that the addition of probiotics and digestive enzymes with different levels of administration in the fermented diet had a significant effect (P<0.05) on the increase in final body weight and percentage of protein retention. The best results were obtained on chicken fed on fermented diet contained 0, 5% digestive enzymes by increasing on final body weight, protein retention, feed conversion and feed efficiency which were higher than fermented feed containing probiotics. In conclusion, it was well known that digestive enzyme effected synergistically on fermented diet in increasing protein retention resulted a higher final body weight of meat chicken.

Fish muscle hydrolysate obtained using largemouth bass Micropterus salmoides digestive enzymes improves largemouth bass performance in its larval stages

The present study utilized digestives tracts from adult largemouth bass (LMB) to hydrolyze Bighead carp muscle and obtain an optimal profile of muscle protein hydrolysates that would be easily assimilated within the primitive digestive tract of larval LMB. Specifically, muscle protein source was digested for the larva using the fully developed digestive system of the same species. The objectives of this study were: 1) to develop an optimal in vitro methodology for carp muscle hydrolysis using LMB endogenous digestive enzymes, and 2) to evaluate the effect of dietary inclusion of the carp muscle protein hydrolysate on LMB growth, survival, occurrence of skeletal deformities, and whole-body free amino acid composition. The study found that the in vitro hydrolysis method using carp intact muscle and LMB digestive tracts incubated at both acid and alkaline pH (to mimic digestive process of LMB) yielded a wide range of low molecular weight fractions (peptides), as opposed to the non-hydrolyzed muscle protein or muscle treated only with acid pH or alkaline pH without enzymes from LMB digestive tracts, which were comprised of large molecular weight fractions (polypeptides above 150 kDa). Overall, the dietary inclusion of the carp muscle hydrolysate improved growth performance of larval LMB in terms of final average weight, weight gain, DGC, SGR, and body length after 21 days of feeding compared to fish that received the diet based on non-hydrolyzed carp muscle. The study also found that hydrolysate-based feed significantly reduced skeletal deformities. The positive growth performance presented by fish in the hydrolysate-fed group possibly resulted from matching the specific requirements of the larvae with respect to their digestive organ development, levels of digestive enzymes present in the gut, and nutritional requirements.

Cross-Kingdom Gene Coexpression Analysis Using a Stemphylium botryosum–Lens ervoides System Revealed Plasticity of Intercommunication Between the Pathogen Secretome and the Host Immune Systems

Necrotrophic pathogens are responsible for significant declines in crop yield and quality worldwide. During the infection process, a pathogen releases a series of secretory proteins to counteract the plant immune system, and this interaction of pathogen and host molecules determines whether the pathogen will successfully invade the host plant tissues. In this study, we adopted co-transcriptomic approaches to analyze the Lens ervoides–Stemphylium botryosum system, with a focus on 1,216 fungal genes coding for secretory proteins and 8,810 disease-responsive genes of the host 48, 96, and 144 h postinoculation, captured in two F9 recombinant inbred lines (RILs) displaying contrasting disease responses. By constructing in planta gene coexpression networks (GCNs) for S. botryosum, we found that the pathogen tended to co-upregulate genes regulating cell wall degradation enzymes, effectors, oxidoreductases, and peptidases to a much higher degree in the susceptible host LR-66-577 than in the resistant RIL LR-66-637, indicating that the promotion of these digestive enzymes and toxins increased S. botryosum virulence. Construction of cross-kingdom GCNs between pathogen and plant for the two RILs revealed that the co-upregulation of these fungal digestive enzymes and toxins simultaneously promoted a series of defense responses such as redox change, expression of membrane-related genes and serine/threonine kinase, and stress and disease responses in the susceptible RIL which was not observed in the resistant RIL, indicating that these activities exacerbated susceptibility to S. botryosum. [Formula: see text] Copyright © 2021 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license .