Levels Of Corn Gluten Meal Research Articles

Effect of soybean meal replacement with corn gluten meal on the survival, biochemical and metabolic responses, and disease resistance of Pacific white shrimp (Litopenaeus vannamei)

Abstract This study delves into the potential of replacing soybean meal (SBM) with corn gluten meal (CGM) in the diet of Litopaeneaus vannamei. We aimed to investigate the effects of a dietary soybean meal replacement on various aspects of shrimp, including survival, biochemical indices, digestive enzymes, metabolomics, and disease resistance against Vibrio harveyi. To conduct the study, we fed 840 juvenile Pacific shrimp seven different diets, each containing varying levels of CGM. The control group received a diet with 0% CGM; the other diets contained 3%, 5%, 7%, 9%, 12%, and 14% CGM. Each group comprised three replicates, and the shrimp were fed their diets for eight weeks. Our findings revealed that the survival rate of the shrimp ranged from 90.83% to 97.50% and did not differ significantly between the control and those fed diet treatments 2–5. Additionally, there were no significant differences in crude protein, moisture, and lipid content. However, we observed that total antioxidant capacity content increased with the dietary inclusion of CGM. Furthermore, malondialdehyde content decreased with increasing CGM levels, while superoxide dismutase increased, indicating no obvious oxidative damage was observed in CGM treatment groups. Interestingly, shrimp fed diets 2 and 3 had considerably lower alanine aminotransferase activity than shrimp in the control group. The disease resistance in shrimp was improved across all treatment groups, with a notably higher CGM inclusion having the highest level of mortality during the challenge test. Finally, we analyzed the metabolomics data and found PCA score plots clearly separated the control group and shrimp fed CGM diets. Our study revealed that a 3% substitution rate of SBM with CGM can enhance survival and immunity, regulate metabolites and improve disease resistance.

Implications of dietary soybean meal replacement with corn gluten meal on growth performance, antioxidant activities, hepatopancreatic histopathology, and intestinal flora of juvenile Pacific shrimp (Litopenaeus vannamei)

This study aimed to investigate the potential of replacing soybean meal (SBM) with corn gluten meal (CGM) in the diet of Pacific white shrimp (Litopaeneaus vannamei). The study examined the effects of a dietary soybean meal replacement on growth, biochemical indices, antioxidant activities, histology, and intestinal flora. A total of 840 juvenile Pacific shrimp were fed seven diets containing different levels of CGM, ranging from diet 1 (diet1) 0% (control), diet2 (3%), diet3 (7%), diet4 (9%), diet5 (11.8%), diet6 (12.7%), and diet 7 (14.4%). The experiment was conducted over 56 days, with three replicate of each group (initial mean weight = 0.13 0.00 g). The results showed that dietary CGM significantly increased final body weight, average weight gain, and specific growth rate. However, the inclusion of dietary CGM decreased with higher levels. The feed conversion ratio of diets 2 and 3 was considerably lower than that of the control group. The activities of alkaline phosphatase and acid phosphatase increased significantly with the feeding of CGM, while the levels of alanine aminotransferase and aspartate aminotransferase decreased significantly. The histology of the hepatopancreas showed an evident epithelial tubule (E, B, R, and F), and the number of intact epithelial cells increased considerably with the increasing inclusion of CGM (P < 0.05). The intestinal flora in the shrimp intestine responded favorably to the replacement of SBM with CGM in the dietary CGM treatment groups, including a number of beneficial bacteria such as Bacteroidetes and Firmicutes. Moreover, with rising CGM levels, diversity indices and richness estimates rose. The regression model with a broken line was found to describing the relationship between the growth rate and the optimal level of CGM required. The results showed that a CGM dose of 3.31% was the most effective for achieving optimal growth performance in juvenile L. vannamei.

Influence of fish meal replacement with graded levels of corn gluten meal on performance, feed efficiency, body chemical analysis and economic revenue of the Nile tilapia fish Oreochromis niloticus

Influence of fish meal replacement with graded levels of corn gluten meal on performance, feed efficiency, body chemical analysis and economic revenue of the Nile tilapia fish Oreochromis niloticus

Growth and Feed Digestibility of Sangkuriang Catfish with Corn Gluten Meal-Based Feeding

Diet testing was conducted for 50 days to investigate the growth and feed digestibility of Sangkuriang catfish with corn gluten meal (CGM)-based feeding. This involved 5 treatments with different levels of CGM in the feed 0, 75, 150, 225, and 300 g.kg−1 for three replications. The result showed that the value of SGR ranged from 0.87 to 1.51 %.day−1, the SGR values with CGM at 0, 75 and 150 g.kg−1 were significantly higher than the values in CGM 225 and 300 g.kg−1. The best value of protein and lipid digestibility were recorded with CGM at 0, 75 and 150 g.kg−1 compared to CGM at 225 and 300 g/kg. A greater propensity for higher CGM levels to negatively impact on growth and feed digestibility of Sangkuriang catfish. Therefore, CGM is confirmed to process the potential for application at a level of 150 g.kg−1 in the Sakuriang catfish diet without negatively influencing growth and feed digestibility.

Effects of replacing fish meal with corn gluten meal on growth performance, intestinal microbiota, mTOR pathway and immune response of abalone Haliotis discus hannai

Corn gluten meal (CGM) is used as a protein source in aquafeeds. However, the potential for replacing fish meal (FM) with CGM in abalone feeds has not been adequately evaluated. A 110-day feeding trial was conducted to evaluate effects of replacing FM with CGM on abalone Haliotis discus hannai (initial weight: 21.83 ± 0.25 g). The control diet (CGM0) was designed to contain 20% of FM. The other four isonitrogenous (about 30% of crude protein) and isolipidic (about 4% of crude lipid) experimental diets were formulated with CGM protein replacing 25%, 50%, 75% and 100% of dietary FM protein, respectively. The five experimental diets were named as CGM0, CGM25, CGM50, CGM75 and CGM100, respectively. Results showed that no significant differences were found in survival rate among all the groups. Weight gain rate (WGR) of abalone in the CGM100 group was significantly lower than that in the control group. There were no significant differences in WGR among the CGM25, CGM50, CGM75 and the control groups. The increasing dietary CGM inclusion level elevated the operational taxonomic units, ACE estimator and Chao1 estimator, and changed the intestinal microbiota composition in abalone. The activities of trypsin, alanine transaminase, aspartate transaminase and Na+, K+-ATPase in digestive gland were significantly decreased when replacement level over 50%. The increasing dietary CGM inclusion level significantly downregulated the expressions of ribosomal S6 protein kinase (s6k), mammalian target of rapamycin (mtor) and eukaryotic translation initiation factor 4E (eif4e) in digestive gland. The CGM75 and CGM100 groups had significant lower activities of catalase and lysozyme in cell-free hemolymph and digestive gland. In conclusion, CGM could replace 75% of dietary FM (equivalent to 16.2% of CGM inclusion level in the diet) without significantly affecting the growth of abalone. However, high inclusion levels of CGM in diets (> 10.8%) had negative effects on intestinal microbiota, mTOR pathway and immunity in abalone.

Growth Responses of Hybrid Catfish (Hetero-clarias) Juveniles Fed All Plant: Protein Diets Supplemented with L-lysine and L-methionine

A 70 day feeding trial was conducted to evaluate the utilization of all plant- protein diets supplemented with L-lysine and L-methionine by Hybrid catfish (Hetero-clarias) juveniles. At the start of the experiment, fifteen (15) glass aquaria tanks (70 cm × 45 cm × 40 cm)/each, filled with borehole water up to 70 L of its capacity were stocked with one hundred (150) Hetero-clarias juveniles (Av. Wt. 16.49 ± 0.02 g)/one at 30 fish per treatment in three replicates in a complete randomized design. Five diets (D1-D5) isonitrogenous (40% Crude Protein) and isocaloric (12.1kcal/kg) were formulated. Except the control (D1), varying levels of Corn Gluten Meal (CGM) of 60% crude protein (CP) as main plant protein source were added to other plant protein materials such as Soya bean meal and Groundnut cake to formulate diets (D2-D5). Fish were fed at 5% body weight twice daily (8.00 and 10:00) for 10 weeks. Water quality parameters were monitored daily. Mean Weight Gain (MWG), Specific Growth Rate (SGR), Feed Conversion Ratio (FCR), Protein Efficiency Ratio (PER) and Net Protein Utilization (NPU) were determined. Proximate and mineral composition of the diets and fish were determined using AOAC methods. Fish fed D1 (control) significantly (P˂0.05) had the best growth performance in terms of final mean weight gain (44.54 ± 0.02)g; Specific Growth Rate (1.86 ± 0.06) and Protein Efficiency Ratio (1.11 ± 0.04). The mean value for Feed Conversion Ratio (FCR) was significantly (P˂0.05) highest (1.4 ± 0.04) in fish fed. Least mean value (8.00 ± 0.03) for Net Protein Utilization (NPU) was also recorded in fish fed D5. Fish fed D2 with minimal plant materials exhibited feed utilization close to D1 (100%FM) as reflected in the growth performance. Fish growth was significantly impaired from (D3-D5) despite supplementation with amino acids, suggesting that inclusion of all-plant protein materials in the diets of Hetero-clarias at this stage of growth should not be encouraged.

Corn gluten meal in pacu Piaractus mesopotamicus diets: effects on growth, haematology, and meat quality

Corn gluten meal (CGM) has a high protein content and absence of antinutrients. However, it has high levels of carotenoids that can cause a yellowing of fish fillets and impair further commercialisation. Graded levels of CGM were incorporated in pacu diets to replace soybean meal (SM) protein. The experimental diets were formulated to be isonitrogenous (220 g kg−1 digestible protein) and isoenergetic (13.4 MJ kg−1 digestible energy) with 0, 25, 50, 75, and 100 % replacement of SM protein by CGM protein over a 60-day period. One hundred fish (32.79 ± 3.43 g) were randomly distributed in 20 experimental cages (70 L) placed within five (1000 L) aquaria with continuous water renewal. The experimental design was completely randomised with five treatments and four replicates. A quadratic effect (P 0.05) for blood parameters, proximal composition, water-holding capacity, pH, lipid oxidation, and a* value of fillets. The L* and b* values of fillets showed differences (P < 0.05). Replacement between 21.95 and 38.75 % of SM protein by CGM protein (5.37 and 9.48 % of inclusion in the diet) improves the growth performance and body yield of pacu juveniles without altering blood parameters or affecting the fillet quality.

Reduction of carotenoids in corn gluten meal: Effects on growth performance and muscle pigmentation of rainbow trout (Oncorhynchus mykiss)

Saez, P. J., Abdel-Aal, E. M. and Bureau, D. P. 2015. Reduction of carotenoids in corn gluten meal: Effects on growth performance and muscle pigmentation of rainbow trout (Oncorhynchus mykiss). Can. J. Anim. Sci. 95: 79-92. Corn gluten meal (CGM) is an ingredient widely included in aquaculture feeds. The use of significant levels of CGM in diet formulation has been anecdotally related to the suboptimal pigmentation of the muscle of salmonid fish. The results of a few scientific studies that have examined the effect of CGM on muscle pigmentation in salmonids remain inconclusive. Therefore, a bench-scale study was carried out to reduce the content of yellow xanthophyll carotenoids in CGM using white soy flake flour as a bleaching agent. A 12-wk growth trial was then conducted to assess the effects of treated CGM on growth and muscle pigmentation of rainbow trout (Oncorhynchus mykiss) in comparison with regular CGM. Results of the pigment reduction study indicated that the concentration of lutein, zeaxanthin...

Reduction of carotenoids in corn gluten meal: Effects on growth performance and muscle pigmentation of rainbow trout (Oncorhynchus mykiss)

Saez, P. J., Abdel-Aal, E. M. and Bureau, D. P. 2015. Reduction of carotenoids in corn gluten meal: Effects on growth performance and muscle pigmentation of rainbow trout (Oncorhynchus mykiss). Can. J. Anim. Sci. 95: 79–92. Corn gluten meal (CGM) is an ingredient widely included in aquaculture feeds. The use of significant levels of CGM in diet formulation has been anecdotally related to the suboptimal pigmentation of the muscle of salmonid fish. The results of a few scientific studies that have examined the effect of CGM on muscle pigmentation in salmonids remain inconclusive. Therefore, a bench-scale study was carried out to reduce the content of yellow xanthophyll carotenoids in CGM using white soy flake flour as a bleaching agent. A 12-wk growth trial was then conducted to assess the effects of treated CGM on growth and muscle pigmentation of rainbow trout (Oncorhynchus mykiss) in comparison with regular CGM. Results of the pigment reduction study indicated that the concentration of lutein, zeaxanthin, β-cryptoxanthin and β-carotene was reduced by 86, 97, 100 and 100%, respectively, in the treated CGM. Results of the growth trial showed that the inclusion of treated or regular CGM in the diet did not significantly affect growth performance. However a significant (P&lt;0.05) reduction in astaxanthin deposition was observed in the muscle of fish fed the diet supplemented with 190 g kg−1 of regular CGM when compared with the fish fed the control diet (0 g kg−1 of CGM). The muscle of fish fed the diet containing 190 g kg −1 of treated CGM showed the lowest astaxanthin deposition. This could be attributed to the presence of reactive peroxy radicals produced during the reduction of carotenoids in the treated CGM. Further research is underway to improve the processing method for the reduction of carotenoids in CGM.

Feeding increasing levels of corn gluten meal induces suboptimal muscle pigmentation of rainbow trout (Oncorhynchus mykiss)

A 24-week growth trial was conducted to evaluate the effects of feeding levels of corn gluten meal (CGM) on growth performance and pigment deposition in the muscle of rainbow trout (Oncorhynchus mykiss). Three isonitrogenous and isoenergetic (digestible energy basis) experimental diets were formulated to contain increasing levels of CGM (0%, 9% and 18%) and 50 mg kg � 1 of astaxanthin. Each diet was fed in triplicate to groups of 75 fish (initial average body weight = 549 g fish � 1 ) reared at 8.5°C. The inclusion of CGM did not significantly (P > 0.05) affect final body weight, thermal growth efficiency (TGC) or feed efficiency. Carotenoid concentration determined by liquid chromatography showed a significant (P < 0.05) linear reduction in the concentration of one astaxanthin isomer, all-trans astaxanthin and all-trans lutein in the muscle of fish in response to increasing levels of CGM. Tristimulus colour analysis of the muscle showed a significant (P < 0.05) linear reduction in a* (redness) and C*ab (chroma). Salmofan TM score showed a significant (P < 0.05) linear and quadratic reduction in response to increasing levels of CGM. In conclusion, the inclusion of CGM up to 18% does not significantly impact growth performance of rainbow trout. However, the concentration of all-trans astaxanthin as well as the expression of important colour attributes of the muscle can be negatively affected at levels exceeding 9% of CGM in the diet. More research on this topic is needed to discern the mechanism(s) behind the negative effects of dietary CGM and/or its intrinsic yellow pigments on muscle pigmentation of rainbow trout.

Utilization of corn gluten meal as a protein source in the diet of white shrimp Litopenaeus vannamei

A 57-day feeding trial was designed to assess the potential of corn gluten meal (CGM) as a plant protein source in practical feeds for white shrimp Litopenaeus vannamei. Five experimental diets providing 350 g kg−1 protein and 110 g kg−1 lipid were prepared, where 0%, 25%, 50%, 75% and 100% of fishmeal (FM) protein was substituted by protein from CGM. The results showed that partial or complete replacement of FM with CGM did not affect survival. The growth of the shrimp declined as the levels of CGM increased, diets containing CGM showing a significantly lower final weight (3.2–5.9 g) and specific growth rates (1.7–2.7% per day) compared to those fed on the diet with 0 CGM (7.1 g and 3.0% per day). Feed conversion ratio was also significantly affected by CGM level. The inclusion of CGM resulted in a statistical decrease in the apparent digestibility (AD) of dry matter from 77.9% to 66.0% and in AD of protein from 80.5% to 52.0%, of feed. The AD of amino acids, with the exception of lysine, declined with the dietary incorporation of CGM. In summary, reduced palatability, low protein digestibility and a deficiency of lysine and methionine seem to be the major reasons behind a depressed growth in shrimp fed on CGM protein-based diets.

Evaluation of feed utilization and growth performance of juvenile striped catfishPangasianodon hypophthalmusfed diets with varying inclusion levels of corn gluten meal

A nutrition trial with striped catfish (Pangasianodon hypophthalmus) juveniles was undertaken to evaluate the effect of replacing dietary fishmeal (FM) protein with corn gluten meal (CGM). A diet with FM as the main protein source was used as the control diet (FM). Five experimental diets (approximately 320 g kg−1 crude protein) were formulated to progressively replace 20% (CGM20), 40% (CGM40), 60% (CGM60), 80% (CGM80) and 100% (CGM100) of FM protein. Fifteen fish per tank (initial weight 11.2 ± 0.6 g) were randomly distributed into 18 80-litre fibreglass tanks connected to a closed recirculation system (temperature 30.3 ± 1.0 °C). The diets were tested in triplicate for 12 weeks. The final weight and specific growth rate (SGR) of fish fed diets CGM20, CGM40 and CGM60 were not significantly different compared to fish fed the FM diet. Feed intake (FI) tended to decrease with increasing dietary CGM level. Striped catfish fed FM, CGM20 and CGM40 had significantly lower feed conversion ratio (FCR) compared with fish fed CGM80 and CGM100 (P < 0.05). The protein efficiency ratio (PER) of fish fed the CGM80 and CGM100 diets was significantly lower than those of all other treatments (P < 0.05). Total ammonia-nitrogen (TAN) excretion increased with elevated dietary CGM inclusion. The viscerosomatic index (VSI) of fish fed the CGM80 and CGM100 diets were significantly higher (P < 0.05) than those of fish fed the other treatments. The crude lipid content in the final body composition of the striped catfish was elevated significantly with increasing dietary CGM levels. Fish fed the CGM80 and CGM100 diets displayed haematocrit levels significantly lower (P < 0.05) than those fed the other diets. The haemoglobin content in fish was significantly higher in fish fed CGM20 and lower at CGM100 compared to fish fed the FM diet. The results of the present trial indicated that the optimum level of FM protein replacement with CGM determined by quadratic regression analysis was 25.1% on the basis of maximum SGR.

Performance of juveniles of Pseudoplatystoma fasciatum fed graded levels of corn gluten meal

The objective of this work was to evaluate corn gluten meal (CGM) as a substitute for fish meal in diets for striped catfish (Pseudoplatystoma fasciatum) juveniles. Eight isonitrogenous (46% crude protein) and isoenergetic (3,450 kcal kg-1 digestible energy) diets, with increasing levels of CGM - 0, 6, 12, 18, 24, 30, 36, and 42% -, were fed to juvenile striped catfish (113.56±5.10 g) for seven weeks. Maximum values for weight gain, specific growth rate, protein efficiency ratio and feed conversion ratio, evaluated by polynomial quadratic regression, were observed with 10.4, 11.4, 15.4 and 15% of CGM inclusion, respectively. Feed intake decreased significantly from 0.8% CGM. Mesenteric fat index and body gross energy decreased linearly with increasing levels of CGM; minimum body protein contents were observed with 34.1% CGM. Yellow pigmentation of fillets significantly increased until 26.5% CGM, and decreased from this point forth. Both plasma glucose and protein concentrations decreased with increased CGM levels. The inclusion of 10-15% CGM promotes optimum of striped catfish juveniles depending on the parameter evaluated. Yellow coloration in fillets produced by CGM diets can have marketing implications.

UTILIZATION OF CORN GLUTEN MEAL AS A PROTEIN SOURCE IN DIETS FOR GILTHEAD SEA BREAM (Sparus aurata L.) JUVENILES

The utilization of corn gluten meal (CGM) was evaluated as a partial fish meal (FM) substitute in practical diets for gilthead sea bream juveniles. Four test diets (isonitrogenous and isoca-loric, 52% protein and 10% lipid, 19 kJ/g diet) containing increasing levels of CGM were for-mulated to replace anchovy meal at levels of 0%, 10%, 20%, and 30%. Triplicate groups of ju-venile sea bream (initial body weight of 1.5 g) were reared in a Recirculating Aquaculture System (RAS) over 45 days at 18±2°C. Fish fed a diet containing 10% of CGM showed com-parable growth performance similar to the control diet containing FM as the sole protein source. No mortality was observed in all treatment groups. Dietary CGM inclusion levels of 20% and 30% showed lower growth performance, feed utilization, and protein efficiency com-pared to the control and the 10% CGM inclusion diets. However these values were not signifi-cantly different among fish fed the CGM10 and CGM20 diets. Economical analyses also con-firmed the growth related experimental results in terms of best profit obtained with the 10% CGM inclusion diet. Results in the present study showed that CGM alone without any amino acid supplements can substitute FM up to 10% with no adverse effects on growth performance, feed utilization, or economical inputs in gilthead sea bream juveniles.

Soil Amendments in Transition to Organic Vegetable Production With Comparison to Conventional Methods: Yields and Economics

Many producers who have used conventional production methods for vegetables, and who want to convert to organic production, will have to pass through a 3-year transition period before their land can be qualified for organic certification. This transition can produce unique challenges. Use of several amendments has received interest for inclusion in organic production. How these affect vegetable production during the transition period was examined. Land was taken from perennial pasture and converted to production of the vegetables: bell pepper (Capsicum annuum L.), cv. Jupiter; processing cucumber (Cucumis sativus L.), cv. Earli Pik; and sweet corn (Zea mays L.), cv. Incredible (se endosperm genotype) using organic materials and methods with comparison made to production using conventional methods. Conventional and transition to organic portions of the field were separated by 25 m with the buffer zone planted with the same sweet corn cultivar used in the experimental plots and minimally maintained by addition of organic fertilizer. To the organic portion of the field, three levels of humates (0, 112, and 224 kg·ha–1) and three levels of corn gluten meal (0, 448, and 896 kg·ha–1) were applied in nine combinations. Yields for all crops were determined for all years. In the first year, bell pepper yields for plants under conventional production were higher than for the plants in the transition plots. In the remaining 2 years, bell pepper yields were similar under the two production systems. In the first 2 years, cucumber yields for plants under conventional production were higher than for the plants under transition to organic production. In the last year, cucumber yields were similar under the two production systems. In all years, sweet corn yields for plants under conventional production were higher than for plants under transition to organic production. Humates and corn gluten meal did not benefit yields of crops. An economic analysis comparing yields, prices, and costs of production of the crops under conventional and the transition to organic indicated that conventional practices generally provided more net revenue than did transition to organic production. Net revenue for the three species under the transition to organic for the 3 years was $2749 for three hectares. Net revenue for the three crops under conventional production for 3 years was $61,821, a difference of $59,072. Costs, yield, and prices will have to be considered when decisions are made concerning the adoption of organic practices.

Influence of post-calving supplemental protein on calf performance and reproductive efficiency for beef cows fed silage

Protein supplementation for winter-calving beef cows between calving and turnout to pasture was studied in two trials. Changes in cow body weight (BW) and condition and calf BW gains were recorded from calving to weaning in the fall. Reproductive performance was monitored, and in trial 2, milk production was determined. In trial 1, multiparous silage-fed cows were allocated to one of five levels of corn gluten meal (CGM): 0, 200, 400, 600 and 800 g d−1. In the second trial, cows were allocated to either restricted or ad libitum silage feeding in combination with three protein supplements: no protein, 400 g d−1 CGM or 475 g d−1 soybean meal (SBM). In trial 1, cows gained weight during supplementation, but on pasture they lost weight (linear effect, P = 0.10). Calf gains and weights at turnout and weaning showed a quadratic response to protein supplementation (P &lt; 0.05). There was a trend toward a linear decline in days to first service with increasing levels of CGM (P &lt; 0.10). In trial 2, cows on restricted silage feeding lost weight (P &lt; 0.05) and body condition (P &lt; 0.10), whereas those fed ad libitum silage gained weight and condition. On pasture, this pattern of weight change was reversed (P &lt; 0.05). Protein supplementation did not influence BW change but tended to cause a lower body condition score at turnout (P = 0.10). Restricting silage intake to the cow did not affect calf performance, but protein supplementation increased gains both during supplementation and on pasture, thus increasing weaning weights (P &lt; 0.05). When silage was fed ad libitum, SBM was more effective than CGM for increasing calf gain. However, when silage was restricted, CGM was more effective. Restricting silage intake did not impair milk production, but feeding CGM increased milk production (P &lt; 0.05). For ad libitum-fed cows, protein supplementation increased pregnancy rate; restricting feed had the opposite effect. Our data suggest that protein supplementation to silage-fed beef cows in good body condition can increase calf performance; however, the level of supplementation is critical, and possible adverse effects on breeding have to be taken into account, particularly with cows in negative energy balance after calving. Key words: Beef cow, protein, milk production, calf gains, silage

Corn gluten and meat and bone meals as protein sources in diets for gilthead seabream ( Sparus aurata): Nutritional and histological implications

Two experiments were conducted to compare the effect of the partial substitution of fish meal by two different protein sources, corn gluten (CGM) and meat and bone meals (MBM) in diets for juveniles gilthead seabream. Growth, feed efficiency, protein efficiency ratio and protein productive values were not significantly affected by the source of dietary protein, although higher values were observed with diets containing increasing levels of meat and bone meal. No differences were found in fish proximate composition at the end of the experiment. Histological studies of liver tissue showed no liver alteration in fish fed diets including increasing levels of corn gluten meal. On the contrary, an increased deposition of lipids, nuclei polarization and isolated necrotic focus were found in hepatocites of fish fed diets exceeding 20% of meat and bone protein. Apparent protein digestibility (ADC) in diets containing CGM showed similar results to those obtained with the control diet. However, a significant reduction in digestibility was observed when MBM was used as partial substitute of fish meal protein. A negative correlation between dietary ash content and protein digestibility was observed. Higher amounts of nitrogen were excreted as levels of CGM and MBM increased in the diets, being significantly higher in the case of 40% substitution either with CGM or MBM protein.