•Inclusion of larval frass improves growth and protein utilization of juvenile hybrid tilapia.•Dietary larval frass, improved natural complement activity of tilapia.•Dietary larval frass appears to ...be beneficial in increasing resistance of hybrid tilapia to Flavobacterium columnare and Streptococcus iniae infections.•Larval frass appears to be a suitable ingredient for use in tilapia diets at least at levels up to 30%.
Frass, a by-product of the larval meal industry, is heterogeneous and includes larval excrement, exoskeleton sheds and residual feed ingredients along with abundant nutrients, chitin and beneficial microbes. The present study was performed to evaluate the changes in growth, feed utilization, body composition, hematology, serum chemistry, immune responses and disease resistance of hybrid tilapia, Nile x Mozambique (Oreocromis niloticus x O. mozambique) fed diets containing frass from black soldier fly larvae, Hermetia illucens. Five diets containing frass at levels of 0, 5, 10, 20, and 30% as partial replacements of a combination of soybean meal, wheat short and corn meal on an equal protein basis were fed to juvenile hybrid tilapia (2.6 ± 0.035 g) in quadruplicate aquaria to apparent satiation twice a day for the first two weeks and once daily for rest of the feeding trail. Final weight gain was significantly increased in fish fed the diet including the highest level of frass (30%). Fish fed diets containing frass (5% to 30%) had significantly higher protein efficiency than the group fed diet without frass (control diet). Feed intake and feed utilization efficiency were not significantly affected by dietary treatments. Survival during the feeding trail, whole-body composition, hematological parameters, and serum biochemistry were not affected by dietary treatment. Serum complement activity of fish fed 30% dietary frass was significantly higher than that of fish fed other treatments. Fish fed the diets containing frass showed significant dose-dependent trends in survival against both Flavobacterium columnare and Streptococcus iniae challenges. Frass from the larvae of black solder flies fed Distillers’ dried grains with solubles has potential for use as feed ingredient for improving growth of hybrid tilapia. Use of frass in tilapia diets may prove beneficial by improving innate immune components and the resistance of hybrid tilapia against bacterial infection.
Frass is a by-product of the larval meal industry and is currently readily available and competitively priced relative to larva meal. In addition to generally high protein and fat content (21.6% and ...6%, respectively), frass contains abundant nutrients, chitin, and beneficial microbes. This study evaluates the effect of various levels of frass derived from the larvae of black solder flies fed dried distillers’ grains (DDG) with solubles on growth performance, whole body and fillet proximate compositions and selected hemolymph parameters of Pacific white shrimp, Litopenaeus vannamei. Five isocaloric diets containing frass at levels of 0%, 5%, 10%, 20% and 30% as partial replacement of a combination of soybean meal (SBM), cottonseed meal (CSM), wheat short (WS) and corn meal (CM) on an equal protein basis were offered four times daily to Pacific white shrimp. Four replicate groups of 15 shrimp per tank (initial weight 4.06 ± 0.05 g) were offered experimental diets at 4% total body weight daily for 12 weeks. Shrimp in each aquarium were group-weighed and counted at 2-week intervals and feed inputs were adjusted based on observed survival and weight gain. Although no significant differences were observed in final weight gain, survival, and whole-body composition of shrimp among treatments, there appeared to be quadratic trend of growth with increasing dietary levels of frass. Shrimp fed diets with 5% frass, and 30% frass, showed the highest and lowest weight gain, respectively. Percent lipid content of fillet is linearly decreased with increasing dietary levels of frass and shrimp fed 20% and higher dietary frass level had significantly lower level of fillet lipid. Serum from shrimp fed 20% dietary frass significantly increased inhibition of Vibrio parahaemolyticus growth when compared to that of the control group. However, other hemolymph parameters (total hemocyte count, hemocyanin, serum protein and serum cholesterol) were not significantly affected by dietary treatments. Frass can be incorporated in shrimp diets up to 30% as a substitute for a combination of SBM, CSM, WS and CM without affecting their growth performance, body composition, hemolymph parameters.
•Larval frass appears to be a suitable ingredient for use in shrimp diets up to 20% inclusion level.•Shrimp fed diets with 5% frass, and 30% frass, showed the highest and lowest weight gain, respectively.•Serum from shrimp fed 20% dietary frass significantly increased inhibition growth of Vibrio parahaemolyticus.•Shrimp fed 20% and higher dietary frass level had significantly lower level of fillet lipid.
The larval waste, exoskeleton shedding, and leftover feed components of the black soldier fly and its larvae make up the by-product known as frass. In this study, we subjected channel catfish (
) to ...a 10-week feeding trial to assess how different dietary amounts of frass inclusion would affect both systemic and mucosal tissue gene expression, especially in regard to growth and immune-related genes. Fish were divided in quadruplicate aquaria, and five experimental diets comprising 0, 50, 100, 200, and 300 g of frass per kilogram of feed were fed twice daily. At the end of the trial, liver, head kidney, gill, and intestine samples were collected for gene expression analyses. First, liver and intestine samples from fish fed with a no frass inclusion diet (control), low-frass (50 g/kg) inclusion diet, or a high-frass (300 g/kg) inclusion diet were subjected to Illumina RNA sequencing to determine global differential gene expression among diet groups. Differentially expressed genes (DEGs) included the upregulation of growth-related genes such as glucose-6-phosphatase and myostatin, as well as innate immune receptors and effector molecules such as toll-like receptor 5, apolipoprotein A1, C-type lectin, and lysozyme. Based on the initial screenings of low/high frass using RNA sequencing, a more thorough evaluation of immune gene expression of all tissues sampled, and all levels of frass inclusion, was further conducted. Using targeted quantitative PCR panels for both innate and adaptive immune genes from channel catfish, differential expression of genes was identified, which included innate receptors (TLR1, TLR5, TLR9, and TLR20A), proinflammatory cytokines (IL-1β type a, IL-1β type b, IL-17, IFN-γ, and TNFα), chemokines (CFC3 and CFD), and hepcidin in both systemic (liver and head kidney) and mucosal (gill and intestine) tissues. Overall, frass from black soldier fly larvae inclusion in formulated diets was found to alter global gene expression and activate innate and adaptive immunity in channel catfish, which has the potential to support disease resistance in this species in addition to demonstrated growth benefits.
Frass–the by-product of the larva meal industry–was recently shown to be a sustainable ingredient for use in diets of several fish species. Additionally, because of its possible immunomodulatory ...activity and anti-microbial properties, frass may have great potential as an organic method of pathogen control in aquaculture. Five diets containing 0, 5, 10, 20 and 30% frass from black soldier fly larvae, Hermetia illucens, were fed to channel catfish (5.24 ± 0.04 g) in quadruplicate aquaria to apparent satiation twice daily. At the end of the 10-week feeding trial, blood samples were collected from all groups to measure hematological and immune parameters, and to determine the effects of dietary frass on resistance to Flavobacterium covae infection. Hematological parameters (red blood cell count, hemoglobin, and hematocrit)—but not white blood cell count—were improved with the inclusion of frass. Serum glucose levels were significantly lower in fish on the diet with frass than fish on the diet without frass. Fish fed the highest dietary levels of frass (30%) had a significantly higher serum cholesterol level than fish on the control diet. Serum complement activity was significantly higher in fish on diets containing frass at levels of 10% and 20%. No significant differences were observed in other measure serum components including albumin, alkaline phosphatase, alanine aminotransferase, amylase, calcium, phosphorus, potassium, total protein, globulin, thyroxine and lysozyme activity. Even though overall mortality was low (0–17%), fish on the diets containing frass at levels 20% or more showed significantly higher survival than that of control fish or fish on lower levels of dietary frass. The use of frass in the catfish diet may prove beneficial by improving hematological parameters, and select serum immune effectors, and the overall resistance of juvenile channel catfish against F. covae infection.
We evaluated a Saccharomyces cerevisiae fermentation product (Diamond V Original XPC) in hybrid catfish (Ictalurus furcatus x I. punctatus) for its potential effects on growth, blood parameters, and ...disease resistance. The trial featured four levels of inclusion that were added to a commercial 32% protein floating catfish ration. Following six weeks of feeding, we observed marginally heightened resistance to columnaris disease and saw significant changes in the levels of immune effectors in the serum, including lysozyme, complement, and immunoglobulin.
Frass is the by‐product of the larval meal industry and includes larval waste, exoskeleton sheds and residual feed ingredients. Experimental frass was derived from the larvae of black solder flies ...fed distillers' dried grains with solubles and had a protein and fat content of 216 and 60 g/kg, respectively. A 10‐week study was conducted to evaluate the effect of dietary levels of frass on growth, feed utilization, and body proximate and mineral composition of channel catfish, Ictalurus punctatus. Five diets containing 0, 50, 100, 200 and 300 g frass per kg diet were fed to channel catfish (5.24 ± 0.04 g) in quadruplicate aquaria to apparent satiation twice daily. Final weight gain was significantly increased in fish fed diets containing frass at levels from 100 to 300 g/kg. Fish fed diets without frass, and with 300 g/kg frass, showed the lowest and highest feed intake, respectively. Feed and protein efficiencies, however, were significantly lower in fish fed frass at levels of 200 g/kg and higher compared to the control diet. Survival, whole‐body composition and mineral content were not affected by frass. In summary, black soldier fly larval frass has potential as a protein source or just an ingredient for enhancing palatability of catfish diets.
Vibrio parahaemolyticus (Vpara) is the causative agent of Acute Hepatopancreatic Necrosis Disease (AHPND), or Early Mortality Syndrome (EMS) in shrimp. Shrimp, like other invertebrates, lack an ...adaptive immune system and depend solely on innate immunity against invading pathogens. To better understand the defense mechanisms of shrimp to this problematic pathogen, we evaluated the changes in hematology, immunology and biochemical values of the hemolymph from shrimp challenged with V. parahaemolyticus up to 8 days post-challenge. Thirty-six shrimp (12 g) were distributed in 9 tanks (75 L), divided into three groups (non-challenged, challenged with 5 × 102 cfu/shrimp and challenged with 1 × 103 cfu/shrimp) in triplicate. Pacific white shrimp, Litopenaeus vannamei, were administered an inoculum of V. parahaemolyticus under the shell between the 5th and 6th abdominal segment to assess cellular and humoral immune responses. Total hemocyte count (THC) significantly decreased in shrimp challenged with Vpara at 6 h, 12 h and 24 h-post infection. Hemocyte lysate phenoloxidase (PO) activity in Vpara-challenged shrimp at 48 h post challenge was significantly increased compared to that of control shrimp. No significant differences were observed in total plasma protein between plasma from control and Vpara-challenged shrimp. However, shrimp challenged with 5 × 102, and 1 × 103 cfu/shrimp had significantly lower hemocyanin at 6 h and 48 h sampling point, respectively. At 24 h post-challenge, the ≥140 kDa and 70 kDa bands from SDS-PAGE of hemocyanin-concentrated hemolymph lysate samples showed a higher and lower intensity, respectively, in Vpara-challenged group than those of the control group. Plasma from Vpara-challenged shrimp at 6 h and 12 h-post infection significantly suppressed V. parahaemolyticus growth. However, significantly less bacterial growth suppression was observed in plasma of shrimp challenged with higher dose compared to control shrimp at the 192 h post-challenge point. Plasma chemistry parameters did not significantly differ among treatments. The changes observed in hemolymph parameters may be useful indicators of the health status of shrimp.
•Vibrio parahaemolyticus infection decreased total hemocyte count and hemocyanin levels.•Phenoloxidase (PO) activity of hemocytes increased by V. parahaemolyticus infection.•Plasma from V. parahaemolyticus exposed shrimp suppresses bacterial growth.
Frass–the by-product of the larva meal industry–was recently shown to be a sustainable ingredient for use in diets of several fish species. Additionally, because of its possible immunomodulatory ...activity and anti-microbial properties, frass may have great potential as an organic method of pathogen control in aquaculture. Five diets containing 0, 5, 10, 20 and 30% frass from black soldier fly larvae, Hermetia illucens, were fed to channel catfish (5.24 ± 0.04 g) in quadruplicate aquaria to apparent satiation twice daily. At the end of the 10-week feeding trial, blood samples were collected from all groups to measure hematological and immune parameters, and to determine the effects of dietary frass on resistance to Flavobacterium covae infection. Hematological parameters (red blood cell count, hemoglobin, and hematocrit)—but not white blood cell count—were improved with the inclusion of frass. Serum glucose levels were significantly lower in fish on the diet with frass than fish on the diet without frass. Fish fed the highest dietary levels of frass (30%) had a significantly higher serum cholesterol level than fish on the control diet. Serum complement activity was significantly higher in fish on diets containing frass at levels of 10% and 20%. No significant differences were observed in other measure serum components including albumin, alkaline phosphatase, alanine aminotransferase, amylase, calcium, phosphorus, potassium, total protein, globulin, thyroxine and lysozyme activity. Even though overall mortality was low (0–17%), fish on the diets containing frass at levels 20% or more showed significantly higher survival than that of control fish or fish on lower levels of dietary frass. The use of frass in the catfish diet may prove beneficial by improving hematological parameters, and select serum immune effectors, and the overall resistance of juvenile channel catfish against F. covae infection.
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