Suitability of selected raw materials and by-products in formulated feeds for Nile tilapia Oreochromis niloticus and African catfish Clarias gariepinus

Merged with duplicate record (10026.1/1967) on 03.01.2017 by CS (TIS)The current status of global aquaculture production was reviewed with a special emphasis on Africa and in particular Egypt. The main species of interest in this study were tilapia Oreochromis niloticus and African catfish Clarias gariepinus which are gaining popularity and are of considerable importance in the market of farmed fish in this continent and of economic relevance to Egypt and other Middle Eastern countries. Research was principally directed to establishing the suitability of specific feed ingredients and materials that could be included in balanced diets for both species. Various animal and plant by-products were selected to evaluate their nutritional value for either species. The experimental protocols, materials and methods and techniques employed are described for nutritional investigations with tropical freshwater fish. These included the various parameters assessed in the growth and digestibility studies relevant to the species in question. These include Specific Growth Rates (SGR), Feed Conversion Ratios (FCR), Protein Efficiency Ratio (PER) and Apparent Net Protein Utilisation (ANPU). An initial investigation to determine the coefficients of digestibility of protein, amino acids and energy was first undertaken using tilapia as the model warmwater fish species. This investigation was able to provide useful data and information as a prelude for successive growth trials with both tilapia and catfish. Fishmeal, soyabean meal, corn gluten meal, poultry by-products including feathermeal and blood meal were all tested at a variety of inclusion levels in successive trials. Apparent digestibility coefficients (ADC %) for tilapia fed diets containing 60% LT 94 fishmeal and 40% of each ingredient are reported. ADC of dry matter (DM) and protein (CP) and energy (E) for the reference fishmeal diet were 83.99 DM; 92.60 CP; and 93.31E respectively. For each test ingredient, these values were as follows; 1- PBM (56.99 DM; 69.30 CP & 73.47 E), 2- Feathermeal (54.09 DM, 45.53 CP & 49.11 E), 3- Blood meal (76.13 DM; 85.79 CP and 75.96 E), 4- Solvent extracted soyabean meal (85.83 DM; 93.46 CP & 82.16 E), 4- Full fat soyabean meal (75.86 DM; 86.99 CP & 74.84 E). The amino acid availability coefficients reflected the same trends as protein digestibility, and these varied from >87% on average for the essential amino acids in fishmeal, 83% for maize gluten and 85% for solvent extracted soyabean meal with an average of 63% for feathermeal and only 61% for poultry meat meal. The importance of plant protein sources and especially soyabean meal was the focus of a complete nutritional study with juvenile tilapia, The influence of full fat soyabean meal (FFSB) inclusion on growth performance, feed utilisation and the gastrointestinal digestive enzymes was also measured in this experiment. It was found that soyabean meal levels above 50% could reduce growth performance and adversely affect gut enzyme activities. Tilapia fed a series of diets with FFSB (58,63 and 63% + DLmethionine did not perform as well as the control group. SGR values ranged between 2.42 to 2.12, and ANPU between 39.41-34.46. Supplementation of the diet with methionine did not restore performance. Hepatic trypsin and amylase enzyme activity was affected with FFSB (from 12.64-1.43 Units and 4.99-2.76 Units respectively). No affects were detected on general proteolytic activity for stomach, intestine and liver. For studies with African catfish, it was first necessary to assess the different grades of fishmeal that could be employed in suitable reference diets for this species. A Poultry by-product meal (PBM) was further evaluated as a fishmeal replacement source (0- 100%) for this species. Catfish fed dry and wet diets of two types of fishmeal showed significant differences in growth performance. Catfish fed dry diets performed better than those receiving wet diets for both LT94 and white fishmeal sources. SGR were (2.80 and 2.75 dry) and (2.46 and 2.57 wet). FCR (0.97 and 0.80 dry) and (1.30,1.30 wet), ANPU (41.85,52.94 dry) and (31.43,30.9 wet) for LT94 and White fishmeal respectively. The PBM fed catfish showed significant differences in weight gain and feed utilisation. SGR was between 3.57 to 2.83, FCR between 1.61 to 2.25 and ANPU fell from 28.90 to 18.82 for groups' fed the control fishmeal diet towards the maximum level of PBM substitution. Histological examination of liver tissue showed alterations in hepatic morphology with respect to sinusoids and fat accumulation for catfish fed higher amounts of PBM. A restricted inclusion of up to 40% poultry by-product meal could therefore be suggested for practical diet formulations. Further investigations were undertaken to assess the potential for either maize gluten meal (MG) or soyabean meal as substitute protein sources for the African catfish Catfish fed higher inclusions of MG displayed SGR's ranging between 5.28 to 2.79, FCR between 0.81 to 1.53 and ANPU values from 52.33 to 24.99%. All lower performance data were obtained for 75% MG substitution of LT94 fishmeal protein. Further histological examination of liver tissue revealed alterations in hepatic structure associated with higher levels of MG. It was suggested that no more than 25% substitution of fishmeal with maize gluten meal is feasible under the present conditions. In a separate study, catfish fed diets containing different levels of FFSB (58,63 and 63% + DL-methionine) at the expense of fishmeal (LT94), showed significant differences in weight gain. SGR ranged between 3.11 to 2.78, FCR 0.82-0.83 and ANPU between 54.48 to 48.60. Also trypsin activities for intestine ranged between 2.75 to 1.71 Units, liver 1.37 to 1.05 Units and stomach 4.09 to 2.29 Units of activity for increasing levels of FFSB. Hepatic amylase was also reduced from 4.49 to 2.46 Units. General proteolytic activities however, did not show any significant differences between catfish fed different levels of FFSB for the stomach, intestine and liver. The conclusions from each of the nutritional trials were considered and comparisons between the response of tilapia and catfish were made. The advantages of plant based protein concentrates was stressed due to the problems currently existing for animal sources and the expense of fishmeal There were many similarities for the tilapia and catfish and it would seem that both fish species could greatly benefit from improved diet formulations that may meet with their nutritional requirements whilst minimising cost of production. A future strategy of research is presented that includes further work to identify more feed ingredients for potential use in these species

Toxico-histological Effects of Sublethal Concentrations of Lead Nitrate on the Gills of the African Catfish, Clarias gariepinus

170-175This study aimed to investigate the effects of subleathal lead doses on the histological architecture of gills in the freshwater African catfish, Clarias gariepinus. Results revealed three stages of changes after exposure to three doses of lead nitrate. The changes were mild in fish exposed to 16.12 mg/L of Pb (NO3)2 (stage I 20% of LC50) and severe in case of 40% of LC50 (stage II, 32.24 mg/L) and 60% of LC50 (stage III 48.37% mg/L) in comparison to control. The histological examination revealed normal architecture of gills in control fish. Normal gills were characterized with primary gill lamellae with a central hyaline cartilage. However, three-stage changes were observed after exposure to the three doses of lead nitrate. In stage I, a cartilaginous matrix appeared along with loosening of the epithelial lining of the cartilaginous core and abundant vascular spaces were observed on the secondary gill lamellae. An extra cartilaginous matrix, loosening of the epithelial lining of the cartilaginous core, de-shaped gill lamellae, and degeneration of the secondary gill lamellae were noted in stage II. Lesions in the gill pattern in stage III were represented by shortening of the tips of secondary gill lamellae, damaged gill lamellae, a cartilaginous matrix, and hyperplasia. This indicated that lead exposure resulted in severe histopathological changes in the gills in a dose-dependent manner

Toxico-histological Effects of Sublethal Concentrations of Lead Nitrate on the Gills of the African Catfish, Clarias gariepinus

This study aimed to investigate the effects of subleathal lead doses on the histological architecture of gills in the freshwater African catfish, Clarias gariepinus. Results revealed three stages of changes after exposure to three doses of lead nitrate. The changes were mild in fish exposed to 16.12 mg/L of Pb (NO3)2 (stage I 20% of LC50) and severe in case of 40% of LC50 (stage II, 32.24 mg/L) and 60% of LC50 (stage III 48.37% mg/L) in comparison to control. The histological examination revealed normal architecture of gills in control fish. Normal gills were characterized with primary gill lamellae with a central hyaline cartilage. However, three-stage changes were observed after exposure to the three doses of lead nitrate. In stage I, a cartilaginous matrix appeared along with loosening of the epithelial lining of the cartilaginous core and abundant vascular spaces were observed on the secondary gill lamellae. An extra cartilaginous matrix, loosening of the epithelial lining of the cartilaginous core, de-shaped gill lamellae, and degeneration of the secondary gill lamellae were noted in stage II. Lesions in the gill pattern in stage III were represented by shortening of the tips of secondary gill lamellae, damaged gill lamellae, a cartilaginous matrix, and hyperplasia. This indicated that lead exposure resulted in severe histopathological changes in the gills in a dose-dependent manner

Lead Nitrate Induced Histopathological Alterations in the Liver and Intestine of African Catfish Clarias gariepinus Exposed to Sublethal Concentrations

552-557Studies were carried out on the liver and intestine tissue of Clarias gariepinus after exposure to sublethal concentrations of LC50 lead nitrate for 20 days. Fish were distributed into four groups, control (0 mg/L, LC50 of Pb(NO3)2) and three groups exposed to 20, 40 and 60% of the LC50 of Pb(NO3)2 (16.12, 32.24 and 48.37 mg/L respectively). Section of hepatic and intestine tissues showed the normal structure for control group. However, treated hepatic tissues of fish exhibited altered its characteristic architecture, with remarkably high vacuolation in hepatocytes and hepatoctolysis. Also, central vein was dilated and increased hemorrhage in the sections of almost samples from treated fish. Increased number of fibroblasts and Kuppffer cells were observed in the examined sections from treated fish when compared to the control. Therefore, fish treated with 60% LD50 of Pb(NO3)2 observed the proliferation of fibrous in connective tissue particularly near sinusoids and substituting liver parenchyma. Therefore, intestinal sections from the different treated fish groups revealed an evident harmful to intestinal tissue, especially in enterocytes and structures of villi. Also, disturbed longitudinal and circular muscularis were observed, to abnormally dilated, lamina propria, was infiltrated with a huge numbers of inflammatory leukocytes. Mucous secreting goblet cells proliferated and multiplied in all exposed fish

Effects of Sub-lethal Lead Nitrate and Copper Sulfate Concentrations on Hematological Parameters During Long-term Exposure in Nile tilapia (Oreochromis niloticus)

437-441Nile tilapia (Oreochromis niloticus) weighing 51.66 ± 2.42 g were exposed to 0%, 20%, 40%, and 60% of LC50 to either lead nitrate (Pb(NO3)2) or copper sulfate (CuSO4) for 30 days. The Pb(NO3)2 and CuSO4 concentrations employed in the treatments of this study were 8.8, 17.6, and 26.4 mg/L and 2.57, 5.14, and 7.71 mg/l, respectively, and multiple hematological variables were evaluated. The red blood cell (RBC) count for the control group was 2.41 ± 0.13 while those of the treatment groups exposed to 8.8, 17.6, and 26.4 mg/L of Pb(NO3)2 were 2.21 ± 0.10, 1.94 ± 0.16, and 1.36 ± 0.10 × 106/µl, respectively, at the end of the study. Similarly, the hemoglobin (Hb), hematocrit (Hct), mean cell hemoglobin (MCH), mean cell hemoglobin concentration (MCHC), and platelet (PLT( levels significantly decreased as the Pb(NO3)2 concentration increased (p 4, showed decrease in the levels of RBC, Hb, Hct, WBC, and PLT when the concentration of CuSO4 increased, while the MCHC, MCH, and MCV levels significantly increased

Growth Performance and Body Composition of Nile Tilapia Oreochromis niloticus Fed Diets Containing Graded Levels of Seaweed Ulva lactuca

873-878Three experimental diets, including fish meal replaced with different ratios (20%, 40% and 60%) of Ulva lactuca and a seaweed-free control diet were used to evaluate the effect of dietary seaweed incorporation on the growth performance, feed utilization and body composition of the Nile tilapia, Oreochromis niloticus. The experiment lasted for 12 weeks and the results of the growth indicators; final weight (FW), weight gain (WG), percentage of weight gain (WG%), daily growth rate (DGR) and specific growth rate (SGR) indicated no significant differences (P>0.05) between the fish on the control diet (C) and those on a diet with 20% U. lactuca (U20), despite the fact that an outstanding performance of fish growth was accomplished on the control diet. Furthermore, no significant differences among C and U20 for the feed conversion ratio (FCR) and protein efficiency ratio (PER) whereas the feed utilization efficiency, FCR and PER decreased significantly when the proportion of U. lactuca meal was increased to 40% and 60% (U40 and U60). Carcass and muscle composition showed a similarity between the various groups. Moisture, protein and ash content showed an increase in line with the increase in U. lactuca meal in the diets, but the reverse was observed for the lipid level. The present study observed that U. lactuca meal attained considerable performance for feeding the Nile tilapia at dietary inclusion levels up to 20% without undesirable effects on growth performance and feed utilization efficiency

Analysis of reproductive biology and spawning season of the pink ear emperor Lethrinus lentjan, from marine ecosystem

A total of 593 samples of Lethrinus lentjan (Lacepede, 1802) were collected from the Red Sea, Jeddah, Saudi Arabia, to study their productive biology and spawning season of the local population. Sampling was carried out on a monthly basis for a period of one year. The monthly sex ratios indicated that females were dominant throughout the study period, with an overall male:female sex ratio of 1:7.98, although males were larger than females. The highest monthly performance maturation index (PMI), as well as the male and female gonadosomatic index (GSI) and ovarian maturation rate (OMR) were observed in February and March. Histological examination of the gonads confirmed the process of sexual transformation in this fish species, wherein individuals mature first as female, and then change sex to male (protogynous hermaphroditism). Histological sections also showed that the sexual maturation of males of L. lenjtan comprised three main stages, while the sexual development of females could be classified into four main stages. Extended spawning in the form of batches released during different months throughout the year were recorded for this fish species, with the main spawning season in February and March, and an additional, shorter spawning season in September

Effect of dietary fish meal replacement by red algae, Gracilaria arcuata, on growth performance and body composition of Nile tilapia Oreochromis niloticus

A 12-week long feeding experiment was initiated to evaluate the effect of dietary supplementation of red algae, Gracilaria arcuata, on the growth performance, feed utilization and body composition of Nile tilapia Oreochromis niloticus (Linnaeus, 1758). The fish were fed with an algae-free control diet (C) and three experimental diets which replaced conventional fish meal with varying levels of dried G. arcuata (20%, 40% and 60%, represented as G20, G40 and G60, respectively). The growth parameters of final weight (FW), weight gain (WG), percentage of weight gain (WG%), daily growth rate (DGR) and specific growth rate (SGR) were significantly reduced (P < 0.05) at all levels of algae incorporation compared to the control diet. Moreover, the negative impact of Gracilaria meal on the growth performance of Nile tilapia increased as the proportion of algae in the diet increased, with fish on diet G20 exhibiting a significantly higher growth performance than the fish on either of the G40 and G60 diets. On the other hand, the feed utilization parameters feed conversion ratio (FCR) and protein efficiency ratio (PER) did not show significant differences between the fish in the control group and those on diet G20, although poorer FCR and PER outcomes were achieved in the case of fish on diet G60. The content of moisture, protein and ash in muscle and carcass increased as the proportion of Gracilaria meal in the diets increased, but the reverse was true for lipid level. These results indicate that incorporation of less than 20% red algae, Gracilaria arcuata, could be feasible in the diet of Nile tilapia and further studies are recommended to optimize the level of algae to improve growth performance

Effects of Dietary Bioactive Lipid Compounds of <i>Acacia nilotica</i> Bark on Productive Performance, Antioxidant Status, and Antimicrobial Activities of Growing Rabbits under Hot Climatic Conditions

This study aimed to evaluate the efficacy of dietary Acacia nilotica bark bioactive lipid compounds (ANBBLCs) as novel feed additives on the growth performance, carcass criteria, antioxidants, and antimicrobial activities of growing male rabbits. A total of 100 California male weanling rabbits aged 35 days were divided into four nutritional treatments, each of which contained ANBBLCs at concentrations of 0 (control group), 50, 100, and 150 mg/kg diet (n = 25 per treatment, each replication consisting of one animal). The average body weight of the animals was 613 ± 14 g. The experiments lasted for 56 days. Dietary ANBBLC levels linearly improved (p p Lactobacillus increased and Staphylococcus decreased (p < 0.05) in comparison to the control group when ANBBLC levels were added to the diets of rabbits. Rabbit diets supplemented with ANBBLCs increased dressing percentages and decreased abdominal fat. This study shows that ANBBLCs can be used as a feed additive to enhance the growth performance, carcass criteria, antioxidant, and antibacterial properties of growing rabbits

New Insights into the Effects of Microbial Muramidase Addition in the Diets of Broiler Chickens

The study aimed to explore how broiler chickens’ blood biochemistry, breast muscles’ fatty acid profile, growth, intestinal morphology, and immune status would be influenced by adding microbial muramidase (MUR) to the diet. Four hundred 3-day-old male broiler chickens were allocated to a completely randomized design consisting of four nutritional treatments (n = 100 per treatment, 10 chicks/replicate), each containing MUR at levels of 0 (control group), 200, 400, and 600 mg Kg−1 diet, with enzyme activity 0, 12,000, 24,000, and 36,000 LSU(F)/kg diet, respectively. The 35-day experiment was completed. The findings showed that adding MUR to broiler meals in amounts of 200, 400, or 600 mg/kg had no impact on growth performance (p > 0.05) during the periods of 4–10, 11–23, and 24–35 days of age. MUR supplementation quadratically impacted the feed conversion ratio of broiler chicks at 11 and 23 days of age (p = 0.02). MUR addition to the diet significantly and level-dependently enhanced the percentage of n−3 and n−6 polyunsaturated fatty acids (PUFA) in breast muscles (p ≤ 0.01), with no alterations to the sensory characteristics of the breast muscles. Dietary MUR increased most of the morphometric dimensions of the small intestine, with the best results recorded at the 200 and 400 mg Kg−1 levels. MUR supplementation at 200, 400, and 600 mg kg−1 linearly lowered the total cholesterol, triglycerides, and low-density lipoprotein cholesterol level (p p −1 to improve broiler chickens’ fatty acid profile in breast muscles, immunity, and blood biochemistry. MUR addition had no positive influence on the bird’s growth