Guar Meal Research Articles

PSII-17 Effect of dietary β-mannanase supplementation on energy and nutrient utilization in diets fed to broiler chickens: A meta-analysis

Abstract Beta-mannan (β-mannan) is a polysaccharide composed of repeating units of mannose, galactose, and glucose. The increased amount of β-mannan is present in various plant protein sources such as soybean meal, palm kernel meal, copra meal, and guar meal. β-mannan is considered an antinutritional factor for non-ruminant animals. Endo-β-mannanase enzymes are endo-hydrolases that can cleave the internal glycosidic bonds of the mannan backbone. As a result, β-mannanase is used to break down β-mannan in animal feeds, thereby aiming to reduce its potential anti-nutritional effects. Previous research has demonstrated that dietary β-mannanase supplementation improves energy and nutrient utilization in broiler diets possibly by decreasing digesta viscosity in the gastrointestinal tract. However, results from previous studies have been inconsistent, mainly due to variable experimental conditions including animals, experimental design, and environment. Meta-analysis is a useful method to comprehensively evaluate and integrate various results from previous studies, thereby providing reliable and practical insights. Therefore, the objective of this study was to conduct the meta-analysis to evaluate the effect of dietary β-mannanase supplementation on digesta viscosity, and energy and nutrient utilization in diets for broiler chickens. Through an extensive literature search conducted on Scopus, PubMed, Web of Science, and Google Scholar between January 2003 and December 2023, we identified 10 eligible studies. The meta-analysis was performed using the “metafor” package in R software version 4.1.3. (R Core Team, 2023), and the standardized mean difference (SMD) and its 95% confidence interval (CI) were calculated using the random effect model. The results revealed that dietary β-mannanase supplementation increased apparent total tract retention (ATTR) of dry matter (SMD = 1.84; 95% CI: 0.46 to 3.21; P = 0.016), gross energy (SMD = 2.16; 95% CI: 1.19 to 3.12; P = 0.001), and nitrogen-corrected apparent metabolizable energy (AMEn) in broiler diets (SMD = 3.38; 95% CI: 1.63 to 5.14; P = 0.002; Table 1). Moreover, dietary β-mannanase supplementation increased apparent ileal digestibility (AID) of gross energy (SMD = 6.65; 95% CI: 3.78 to 9.53; P = 0.002) and nitrogen (SMD = 1.41; 95% CI: 0.55 to 2.27; P = 0.006) in broiler diets (Figures 1 and 2). Finally, digesta viscosity (SMD = -3.35; 95% CI: -4.69 to -2.02; P < 0.001) in broiler chickens was decreased by dietary β-mannanase supplementation. In conclusion, the current meta-analysis indicates that dietary β-mannanase supplementation improves the overall utilization of energy and nutrients in diets with decreasing digesta viscosity in broiler chickens.

Effect of a Guar Meal Protein Concentrate in Replacement of Conventional Feedstuffs on Productive Performances and Gut Health of Rainbow Trout (Oncorhynchus mykiss)

Effect of a Guar Meal Protein Concentrate in Replacement of Conventional Feedstuffs on Productive Performances and Gut Health of Rainbow Trout (Oncorhynchus mykiss)

Effect of A Partial Substitution of Soybean Meal with Guar Meal on Blood Biochemistry Characteristics in Broiler Chickens

Effect of A Partial Substitution of Soybean Meal with Guar Meal on Blood Biochemistry Characteristics in Broiler Chickens

Physicochemical, structural, and functional characterization of guar meal protein isolate (Cyamopsis tetragonoloba)

Guar korma and churi protein isolates were assessed for their physicochemical, nutritional, functional, structural, and digestibility properties for their application in the food industry. The water extracted protein isolate of guar korma showed a protein content of 89.7 % and a yield of 48.7 %. Water extracted protein isolate of guar korma showed an excellent protein efficiency ratio, essential amino acid/total amino acids (34.35 %), amino acid score, and protein digestibility corrected amino acid score values, suggesting the existence of high-quality proteins. Water extracted protein isolate of guar korma contains all the essential amino acids except Methionine and Cysteine, according to World Health Organization recommendations for children and adults. The protein profiling of water extracted protein isolate of guar korma was analyzed using 12 % sodium dodecyl sulfate polyacrylamide gel electrophoresis and indicated the presence of eight major protein bands in the range of 17–100 kDa. In vitro digestibility of water extracted protein isolate of guar korma showed the complete digestion of the abundant protein bands within 15 min. Further, the foaming capacity, water/oil holding capacity, and emulsifying stability of water extracted protein isolate of guar korma were comparable with soy protein isolate. Fourier Transform Infrared and Circular Dichroism spectral analysis revealed the presence of several aromatic groups and β-sheets, random coils respectively in water extracted protein isolate of guar korma. The morphological nature of the guar protein isolate was characterized by Scanning Electron Microscopy. Overall, these findings support that water extracted protein isolate of guar korma has excellent functional and nutritional properties and could be a potential alternative plant protein in food industries.

Influence of Guar Meal from Pig Compound Feed on Productive Performance, Nitrogen Metabolism, and Greenhouse Gas Emissions

Guar (Cyamopsis tetragonoloba) is an annual legume tolerant to drought. Guar meal (GM) is a protein- and carbohydrate-rich co-product generated after the mechanical separation of the endosperm from the germ and hull of guar seed. GM has received considerable interest in animal feed as an alternative to soybean meal (SM). In this study, we aimed to assess the nitrogen (N) balance indicators, performance, carcass traits, and main greenhouse gas (GHG) emissions resulting from enteric fermentation (E-CH4) and manure (M-CH4 and N2O). Two tests were performed: (i) a biological trial on 45 pigs (15 animals/group) and (ii) a digestibility test in metabolism cages (N = 15, 5 replicates/group). Three different diets were given to the pigs: one diet was based on 0% GM (SM diet); in the second, GM-50%, GM replaced 50% of the SM; and the third was GM-100%, in which GM fully replaced the SM. The GM and SM diets were analyzed for their proximate composition. A model based on prediction equations was used to estimate the GHGs. GM up to 10% in the diets of finishing pigs did not significantly impact growth performance or carcass traits, although a slight increase in neutral detergent fiber (NDF) was observed. GM up to 10% improved N digestibility (p < 0.0001), net protein utilization (p < 0.0001), the biological value of protein, coefficients of metabolizability, and the coefficient of the total tract’s apparent digestibility. Irrespective of its dietary proportion, GM decreased total nitrogen output (TNO, p = 0.11). A highly significant impact was noted for N2O and E-CH4 (for DM, p < 0.0001), as well as a significant impact for E-CH4, expressed as g CO2 Eq (p = 0.007), and g CO2 Eq. LU (livestock unit, p = 0.005), also reported as ADG (p = 0.024). Manure, M-CH4, was not significantly influenced. In conclusion, GM can replace up to 100% SM and is thus a valuable byproduct that does not alter animal performance and can positively impact N2O and E-CH4.

The Effect of Dietary Supplementation with GUAR (Cyamopsis tetragonoloba) Meal Protein on the Quality and Chemical Composition of Pig Carcasses

Abstract Recent research efforts have focused on replacing expensive imported genetically modified soybean meal (GM SBM) as a protein source in animal diets with guar meal characterized by similar nutritional characteristics, which could improve meat quality. The aim of this study was to determine the effect of guar meal protein fed to pigs on carcass quality and the content of major nutrients and fatty acids in the longissimus lumborum (LL) muscle. Pigs were divided into four groups. Control group (1) animals were fed diets containing SBM as the main protein source. In diets for experimental groups 2, 3 and 4, SBM protein was replaced with guar meal protein in 25%, 50% and 75%, respectively. It was found that SBM replacement with guar meal protein at 25% affected carcass weight and the lean content, fat content and protein content of the ll muscle. An analysis of linear correlations revealed a strong negative correlation between the concentrations of monounsaturated fatty acids (MUFAs) and saturated fatty acids (SFAs) in the LL muscle of pigs fed diets containing 25% of guar meal protein, which is nutritionally desirable. The results of this study suggest that the dietary inclusion of guar meal protein at up to 25% of SBM protein has no negative effects on the fattening performance of pigs. Meat quality was not affected by diets fortified with guar meal protein.

Optimization of Age at Maturity in Surti Buffalo Heifers with Dietary Supplementation of Bypass Protein and Bypass Fat

Surti buffaloes heifers reared under ideal feeding and managemental practices achieve puberty, sexual maturity and first calving at the optimum desired age and body weight. In growing heifers during first parity, requirement of high plane of nutrition is obvious to meet the demands of body growth of dam, growth of fetus, and galactopoetic functions. This study was aimed to find out the effect of feeding bypass protein and bypass fat right from the age of puberty up to the age of first successful conception, i.e. maturity in Surti buffalo heifers. Sixteen Surti buffalo heifers were allotted in four equal groups (n=4 in each group), viz., Control (T-1) fed basal diet following ICAR nutrient requirements, T-2 basal diet + 30 % protein of concentrate mixture replaced with formaldehyde treated guar meal (FTGM), T-3 basal diet + 100 gm bypass fat (BF), and T-4 basal diet + 30 % protein of concentrate mixture replaced with FTGM + 100 gm of BF. All the treatment diets were isonitrogenous. The results revealed that there was beneficial effect of feeding by pass protein and bypass fat along with routine feeding management on growth of heifers in terms of the body wt. gain and reduced age at first conception (maturity) and thereby age at first calving (AFC). AFC reduced to 37.25, 37.87 and 33.37 months, respectively, in T2, T3 and T4 groups respectively; compared to 43.75 months in Control group. Further, the net benefit over control, in the group of heifers fed with FTGM alone and FTGM plus BF groups were 22.90 % and 16.40 % respectively.

Evaluation of Growth Performance, Carcass Composition and Meat Quality of Broiler Chickens Fed Rations Containing Guar Meal and Enzyme Preparations

The study aimed to determine the growth performance, carcass composition, and meat quality of broiler chickens fed rations with different levels of guar meal and feed enzymes. Two hundred and forty one-day-old, sexed chicks were assigned to six equinumerous groups (C4, C8, R4, R8, V4 and V8), with five subgroups each. The birds were fed ad libitum with Starter (1-21 days of life), Grower (22-35 days of life) and Finisher (36-42 days of life) comprised of maize meal, soybean meal, guar meal (4 or 8%), oil, and mineral and vitamin additives, in a two-factor pattern as follows: groups C4 4% guar meal without enzyme preparation, C8 8% guar meal without enzyme preparation, R4 4% guar meal + R enzyme preparation, R8 8% guar meal + R enzyme preparation, V4 4% guar meal + V enzyme preparation, V8 8% guar meal + V enzyme preparation. It was demonstrated that a higher (8%) percentage of guar meal in broiler chicken rations significantly contributed to body weight reduction (by 8%) and increased feed conversion ratio (by 3%). Simultaneously, it reduced the dressing percentage (by 2%) and carcass muscularity (by 3%). Feed rations supplemented with enzymes (R or V) did not improve growth performance and did not impact the dressing percentage, carcass muscularity and fatness. The use of 8% guar meal in broiler chicken feed decreased the crude ash content in the muscles, which, by contrast, increased due to enzyme supplementation. A higher level of guar meal reduced the content (by 4%) and fat quality measured as the ratio between n6:n3 PUFA and the index of AI, TI and HH. The results of the study imply that 4% guar meal inclusion in feed rations for broiler chickens not supplemented with enzymes should be recommended.

Effect of feeding guar (Cyamopsis tetragonoloba) meal on selected biochemical indices in blood and morphology liver of pigs

Effect of feeding guar (Cyamopsis tetragonoloba) meal on selected biochemical indices in blood and morphology liver of pigs

EFFECT OF PARTIAL REPLACEMENT OF GROUNDNUT CAKE WITH GUAR MEAL ON BLOOD BIOCHEMICAL PROFILE IN SHEEP FED DENSIFIED CROP RESIDUE BASED COMPLETE FEED BLOCKS

A 120 day trial was conducted to evaluate the effect of replacement of 50% Groundnut cake (GNC) nitrogen with guar meal (GM) on the blood biochemical profile in the ram lambs fed maize and sorghum stover based complete feed blocks. Twenty-four growing ram lambs of 3-4 months age were randomly selected and allocated into 4 groups consisting of 6 animals in each group. The Maize and sorghum stover based complete diets (50 roughage: 50 concentrate) with and without inclusion of GM was prepared and densified into block form and fed to ram lambs. The four dietary treatments were: M1: Maize stover based complete feed blocks (MSCFB) with GNC (34.8% CP) as protein supplement; M 2: MSCFB with guar meal (52 % CP) replacing 50 % GNC nitrogen of M1; S1: sorghum stover based complete feed blocks (SSCFB) with GNC as protein supplement and S2: SSCFB with guar meal replacing 50 % of GNC nitrogen of S2. Blood was drawn at the end of the trial for serum collection and serum metabolites were analyzed according to standard procedures. There was no significant (P>0.05) effect on the concentration of all serum biochemical constituents among the different experimental groups of lambs and all serum biochemical constituents had mean values that were within the normal range. According to the findings of this investigation, replacing 50% GNC nitrogen with GM had no detrimental effect on blood biochemical parameters in lambs.

Efficacy of a novel ß-mannanase on intestinal digesta viscosity in broiler chickens fed diets with high levels of guar meal (Cyamopsis tetragonoloba)

Efficacy of a novel ß-mannanase on intestinal digesta viscosity in broiler chickens fed diets with high levels of guar meal (Cyamopsis tetragonoloba)

The formaldehyde treated guar meal and prill fat, agro industrial by-products as dietary rumen protected protein and energy source: improves growth performance, feed conversion, nutrient utilization, microbial protein synthesis, blood metabolites and economic efficiency in growing dairy buffalo (Bubalus bubalis) calves.

The study investigated the effects of protein replacement with formaldehyde-treated guar meal (FTGM) and prill fat (PF) in the diet on performance of growing dairy buffalo calves. Thirty-two feedlots Surti breed dairy buffalo calves (age, 7.31 ± 0.34months and body weight, 90.69 ± 6.19kg) were assigned into four dietary treatments (n-8 calves/each): (1) control group, supplied basal diet as per ICAR (2013) nutrient requirements; (2) FTGM group, 30% crude protein (CP) requirement of concentrate mixture (dry matter basis (DMB)) replaced with FTGM in basal diet; (3) PF group, supplied basal diet + 100g PF; and (4) FTGM + PF group, 30% CP requirement of concentrate mixture (DMB) replaced with FTGM in the basal diet + 100g PF for 280days. All the treatment diets were isonitrogenous. Growth performance was improved in FTGM + PF and FTGM groups. Apparent digestibility (%) of CP was increased in FTGM and FTGM + PF diet, while digestibility (%) of ether extract (EE) was increased in PF group. Serum total protein, albumen, urea nitrogen, and creatinine concentrations were higher in FTGM + PF and FTGM groups, whereas total cholesterol and triglycerides levels were greater in FTGM + PF and PF groups. Calculated methane emission had a discernible influence of treatment in FTGM and FTGM + PF. The overall cost of feeding per kilogram gain was lowest in FTGM and FTGM + PF groups. In conclusion, 30% CP replacement with FTGM with or without PF improved the growth performance, feed conversion ratio, and nutrient utilization; supported efficient utilization of resources; and economized the rearing of growing dairy buffalo calves.

Effect of fungal fermentation on proximate composition, physical and functional properties of five different plant proteins used in aquafeed formulation

Five different plant proteins such as soybean meal (SBM), groundnut oil cake (GNC), rapeseed meal (RSM), sunflower oil cake (SFC) and guar meal (GRM) were tested for proximate composition as well as physical and functional properties before and after fermentation using Aspergillus niger. Fermentation was carried out in a BOD incubator at 35°C for three days after inoculating with 5% fungal suspension. Results revealed that fermentation significantly (p<0.05) increased the crude protein content and total ash by 12.5 and 10.5%, respectively, while other proximate indices, including crude fat, crude fiber and nitrogen-free extract reduced significantly. The fungal fermentation had no effect on the texture and colour of plant proteins, while fermented samples had slightly fermented odour along with their natural odour. The plant proteins such as SBM, GNC, RSM, SFC and GRM had bulk densities of 0.54, 0.62, 0.79, 0.60, and 0.71 g cm-3 and significantly (p<0.05) increased by 27.1, 0.5, 0.4, 19.9 and 12.3%, respectively. Fermentation significantly (p<0.05) reduced water holding capacity by 11.7% regardless of the ingredients, with the decrease being significantly (p<0.05) greater in GNC (17.7%), RSM (16.4%) and SBM (13.4%). After fermentation, the protein solubility index reduced significantly (p<0.05) from 77.12 to 73.59%, with SBM and RSM having a reduction of about 5.9 and 5.4%, respectively, while GNC and SFC had a reduction of 4%. The difference between fermented and unfermented GRM, on the other hand, was not significant. Results concluded that fermented ingredients could be potential protein sources rather than their counterparts based on their chemical composition and functional properties. Keywords: Aspergillus niger, Fermentation, Functional property, Physical property, Plant protein, Proximate composition

Rearing Performance and Carcass Composition of Broiler Chickens Fed Rations Containing Guar Meal at Graded Levels

This study aimed to evaluate how different percentages of guar meal in feed rations for broiler chickens affect their rearing performance and carcass composition. The experiment was conducted in a group of one hundred sixty Ross 308 broilers randomly allocated to four equinumerous groups (K, G4, G8 and G12). The birds were reared over 42 days with the application of three feeding periods: starter (days 1–21), grower (days 22–35) and finisher (days 36–42). All the feed rations were prepared using maize meal, soybean meal, oil and mineral and vitamin additives. An experimental factor was the share of guar meal in feed rations: group K—0%, G4—4%, G8—8% and G12—12%. It was demonstrated that a higher percentage (8% or 12%) of guar meal in the feed rations had a negative effect on the chickens’ weight gain and feed intake. The birds receiving feed rations supplemented with guar meal featured higher feed conversion levels than those fed rations in which soybean meal was the only protein-rich component (p ≤ 0.05). Birds fed rations with the highest percentage (12%) of guar meal showed a significant decrease in chilled carcass weight and dressing percentage compared with other chickens. A higher percentage (8% or 12%) of guar meal in feed rations had an adverse effect on the birds’ muscularity. In addition, it was demonstrated that their meat was DFD (dark, firm and dry; pH1 > 6.4), but from a dietary point of view, it contained the smallest amount of intramuscular fat. To sum up, 4% of guar meal should be recommended in broiler chicken feeding to ensure their satisfactory rearing performance and carcass composition, including the physico-chemical properties of their muscles.

Effect of feeding of sorghum stover based complete feed blocks containing guar meal as protein supplement on reproductive efficiency, hormone profile and antioxidant status in Deccani ewes.

Guar meal (GM) can be considered as an alternative protein source for the livestock and has a potential value as a feed to animals with a high protein content ranging between 45–55%. A study was conducted to evaluate the effect of partial replacement of groundnut cake (GNC) with guar meal (GM) on reproductive efficiency, hormone profile, antioxidant status in Deccani ewes fed sorghum stover based complete feed blocks (SSCFB). Twenty-one non-pregnant Deccani ewes (b. wt. 23.34 ±0.40 kg; 2–4 years old and body condition score 2.51±0.56) were randomly divided into three groups to contain 7 animals each in a completely randomized design. Three dietary treatments viz. S1: conventional feeding (sorghum stover and concentrate mixture fed separately in 50:50 ratios to meet the requirement), S2: SSCFB with GNC as protein supplement in concentrate mixture and S3: SSCFB with GM replacing GNC nitrogen of S2 at 50% level. The ewes were synchronised for estrus with progesterone impregnated intravaginal sponges and naturally mated. The ewes were fed at the rate of 3.1 and 3.7% of their body weight from 1st day of experiment—to 108th day of gestation and from 108th day of gestation to till lambing, respectively. The replacement of 50% of GNC nitrogen with GM and densification of diet had no effect (P>0.05) on average DMI (g), antioxidant status, progesterone concentration, conception rate, non return rate, no of matings per service, lambing rate, body weights of lambs at birth, 15 and 30 days of age. GNC can be partially replaced by GM in the ewes diet without any adverse effect on reproductive parameters, antioxidant status, progesterone concentration and weight of lambs.

Effect of feed supplementation through multi nutrient feed block (MNFB) on milk production, composition and reproductive behaviour of buffaloes (Bubalus bubalis) – A field study in Arid Rajasthan

The Buffalo rearing is adopting faster rate in arid region of Rajasthan due to its multifaceted utility for both milk and meat. Despite of better management practice are adopted for buffaloes, they also depend upon grazing and poor quality of fodder to meet out their total dry matter intake. The concept of balanced feed with respect to mineral and vitamins are not aware by farmer’s community. Thus, the alternative low cost balanced feed was adopted in buffaloes under field condition to augment the milk production with optimum reproductive efficiency. MNFB was developed at feed technology unit of CAZRI, as solidified block of wheat bran, guar meal, dolomite, -minerals and vitamins mixture powder, salt, molasses and urea solution. The study evaluated feeding effect of multi-nutrient feed block on milk production and reproduction performances of lactating buffaloes. The Buffaloes under treatment were divided randomly into two groups and assigned to two dietary treatments under village condition. After calving, all the buffaloes in treatment group were dewormed with albendazole 3 gms and feeding of MNFB 2 blocks (2 kgs each)/week for 3 months during March to May. The control group received diet containing bajara (Pearl millet) kuti, dry grasses, crushed cotton and til (sesame) cake. Milk production, peak milk yield were increased highly significant. Fat percentage was significantly increased. All Observations were monitored as per format. In reproductive performances were like sign of oestrus, conception and post partum reproductive complication 90%, 86.6% and 0.06% in treatment group and 70%, 60% and 30% in Control group respectively. It was concluded that MNFB feeding improved milk yield, milk fat, general health status and reproductive performance of buffalos, as it is a good source of protein, energy, and minerals. It is recommended that MNFB should be used as a supplementation in lactating buffaloes when they area fed with low quality fodder in arid and semi arid region.

Efficient production of poly-γ-glutamic acid by Bacillus velezensis via solid-state fermentation and its application

A novel glutamate-dependent poly-γ-glutamic acid (γ-PGA)-producing strain Bacillus velezensis CAU263 isolated from Chinese traditional Douchi was evaluated. An efficient method of γ-PGA production was performed by this strain via solid-state fermentation (SSF) using guar meal. The maximal yield of γ-PGA reached 158.5 g/kg dry weight (DW) in 250 mL flasks and 155.1 g/kg DW in shallow tray, respectively. The molecular weight of γ-PGA was 3.8 × 106 Da, the ratio of L/D-glutamic acid was 26.1% and 73.9%. Additionally, γ-PGA significantly improved the operating characteristics of wheat dough, the specific volume of bread was increased by 15.8% and the bread hardness was reduced by 44.2% owing to the addition of 0.3 g/kg γ-PGA. Thus, γ-PGA could be produced by Bacillus velezensis CAU263 at high level using guar meal and might have potential application prospect in food industry.

Evaluation of the Physical Characteristics of Complete Feed Blocks Containing Different Binders

Background: Binders play on important role in providing compactness and hardness to the complete feed block (CFB). Hardness of the block is also important to increase the durability of the block. In this view, the present comprehensive study is being taken up to evaluate the effect of different binders on the physical characteristics of the complete feed blocks. Methods: The complete feed is formulated to contain 10.5% CP and 55% TDN based on ICAR-2013 requirements. Feed blocks were prepared with sorghum stover (Roughage to concentrate ratio 50:50) using different binders such as molasses (M), guar meal (GM) and condensed distillery soluble (CDS) at different levels @ 6%, 8% and 10%. The complete feed mixtures were densified into blocks in horizontal feed block-making machine at 1500 psi for a dwell time of one minute. The feed blocks were stored for 48 hr to dry and evaluated for the physical and drying characteristics. Result: The bulk density and durability was higher (P less than 0.001) in M-8, M-10 and GM-10 feed blocks. The GM-8 blocks had higher bulk density (P less than 0.001) but less durable (P less than 0.001) than the other feed blocks. Durability and bulk density of GM-10 and M-10 blocks were comparable with M-8 feed blocks but the PCE of GM-10 and M-10 blocks was 11.61 and 10.75% higher than the M-8 blocks, respectively. CDS when included at 6, 8 or 10% as a binder, the blocks could not be prepared. Based on these results it was concluded that molasses at 8% is best for preparation of the CFBs.

Effect of fish meal replacement with toasted guar meal on growth, food conversion, digestive enzyme activity and final carcass composition of rohu,Labeo rohita

A growth trial was conducted for 60 days in 4 × 4 m outdoor cement tanks with soil base to evaluate growth, feed conversion efficiency, carcass composition and digestive enzyme activity of rohu, Labeo rohita, fed diets incorporated with guar meal replacing fish meal. The isonitrogenous and isocaloric diets used were—a fish meal based diet (Control) and diets with fish meal replaced at 30%, 60% and 90% levels with guar meal. The growth parameters, feed conversion and protein efficiency ratio, survival and condition factors did not differ significantly among the different treatments. While the activity of the digestive enzymes in the hepatopancreas did not differ (p > 0.05) among the treatments, the activity of digestive enzymes estimated in the intestine showed reduction at higher levels of guar incorporation. Carcass composition analysis revealed the highest moisture and lowest crude protein, fat and gross energy levels in fish from 90% replacement group. Lowest moisture and highest crude protein, fat and energy levels were observed in fish from 30% replacement. The study indicated the possible use of processed guar meal as a fish meal substitute in the diet of rohu, resulting a reduction in feed cost without compromising on fish growth and quality.

Effect of feeding level on the digestibility of alternative protein-rich ingredients for African catfish (Clarias gariepinus)

Apparent digestibility coefficients (ADC) of nutrients and individual amino acids (AA) for 13 feed ingredients as affected by feeding level were determined for African catfish, a species of economic importance in Africa. Results from two trials are reported. In each trial, ADC were determined using a reference diet and test diets with yttrium oxide as indicator. Juvenile African catfish (averaging 53.9 g, trial 1; 40.4 g, trial 2) were stocked in tanks connected to a common recirculation aquaculture system. Ingredients tested included hydrolysed feather meal (HFM), fishmeal (FM), insect meal (IM), soybean meal (SBM), sunflower meal (SFM), poultry meal (PM), corn dried distillers grains with solubles (CDDGS), faba beans (FB), lupine meal (LM), pea protein (PP), guar meal (GM), canola meal (CM) and yeast meal (YM). The effect of feeding level on ADC was determined by feeding fish restrictively (80% satiation) for 5 weeks and subsequently to apparent satiation for 2 weeks. Inclusion of yeast meal at 30% resulted in low palatability. ADC of nutrients were significantly affected by feeding level (except for fat and carbohydrate), but the effect was ingredient-dependent. African catfish was able to digest protein very effectively in almost all tested ingredients with ADC values ranging from 85.6 to 105.1% across feeding periods. Several ingredients tested, including animal protein ingredients and YM had similar high ADC for dry matter as FM. However, the ADC of AA differ among ingredients, indicating a need for digestible amino acid profile data. Methionine (Met) was the first limiting essential amino acid in HFM, FB, and LM with values ranging from 5−6 g/kg, expressed as digestible Met (dMet) per unit of digestible protein (DP), compared to FM (27 g dMet/kg DP). IM had comparable and sometimes higher overall digestible essential AA values compared to FM, except for methionine and lysine. For oilseeds and legumes, SBM tended to be the best quality AA source, as it had the highest digestible essential amino acid profile. These data provide information concerning nutrient and digestible AA values, which will allow a more efficient use of alternative ingredients in African catfish diets. Formulating diets based on the digestible AA in ingredients will aid precise feed formulation, thereby minimising economic losses and reducing the environmental footprint of aquaculture production.