Effects of Fish Meal Substitution with Poultry By-product Meal on Juvenile Nile Tilapia

The global production of tilapia drastically increased from 124 thousand metric tons (Mt) in 1997 to 2.5 million Mt in 2010. This trend suggests that there will be even greater increases in the future. Among the cichlid species, it is the Nile tilapia (Oreochromis niloticus) that has dominated in different culture system. The tilapia market has expanded from a subsistence level to meet the protein needs of the middle class because of the year-round supply, delicious flavour and reasonable price of that fish . Golbal tilapia production was recorded 3.500.000 metric tons in 2011, 3.8000.000 metric ton in 2012,4.850.000 metric ton in 2014 and by 2015, world production tilapia is forecast to reach 4.6-5.0 million metric ton .
Traditionally, fish meal has provided a major part of protein sources in formulated feeds because of its suitable protein quality. Science the recent scarcity and uncertain consistency of supply encourage its replacement by alternative protein sources that are of high quality, but less expensive has been investigated in many fish species. The limitations on the world's food supply provide additional motivation [5,6]. Therefore, numerous studies have undertaken to examine the effects of replacing fish meal by another source of protein such as animal by-product or plant-based protein in diets that can be fed to tilapia .
Animal by-products such as meat meal, bone meal and poultry by-product meal have considerable potential as feed ingredients in fish production system and comparatively less expensive than fish meal . These animal protein ingredients are good sources of amino acids with high protein content, total digestible dry matter and energy similar to fish meal . Therefore, poultry by-product meal is considered a probable replacement for fish meal . Many studies have also shown that animal protein ingredients can be useful for fish feed formulation and they are comparatively much less expensive than fish meal .
Some studies have shown that poultry by-product meal cannot replace more than 50% of fish meal in fish diets , but other studies have shown that with the recent improvement of the quality of poultry by-product meal it could replace 75% or 100% of fish meal without significant decrease in fish growth .
The present study aims to evaluate the effects of use poultry byproduct meal as a alternative protein source to replace fish meal on growth performance, nutrient utilization, digestibility coefficient and some blood constituents of Nile tilapia (Oreochromis niloticus) reared in cement tanks.
Materials and Methods
Fish culture and experimental diets
The present study was conducted using the research facilities of the experimental station at Shakshouk, Fayoum Governorate, National Institute of Oceanography and Fisheries (NIOF). The system contained two water pumps and upstream sandy filter units at a point between the water source and tanks. Each pump was drowning the water from the lake Qaroun to collection cement pond and forced it through storage units and then to the rearing tanks in open system. Physicochemical characteristics of water tanks were examined every week, (Table 1) according to APHA .
The fry of Nile tilapia (Oreochromis niloticus) used in the present study were obtained after brood stock hatching in the station. The fry were acclimatized for two weeks in rearing tanks and fed on prepared powder diet contain 30% crude protein, formulated from the same ingredients use in the growth trial. Juvenile tilapia with an initial average weight of 1.5 ± 0.05 g were randomly distributed and stocked at 100 juvenile per tank in 12 cement tanks, each with a water volume of (2 m3) and the treatments were performed in triplicates. The diets were given at 3% of live body weight (BW) and offered in two equal portions at 10.00 a.m and 16.00 p.m. The experiment lasted 120 days after start.
Four isonitrogenous diets were formulated to contain an average of 30.11 ± 0.07% crude protein for meeting the recommended nutritional requirements of tilapia . The ingredients were obtained from Zoocontrol fish Co at 6 October city, Egypt. Ingredients, diets formulation and chemical composition analysis are presented in Tables 2 and 3. The first diet was formulated without poultry by-product meal and considered as a control diet (PM0), Diets 2 (PM50), 3 (PM75) and 4 (PM100) were formulated to be comprised with partial and total inclusion levels of 50, 75 and 100% poultry by-product meal, respectively. All diets were processed into dry sinking pellet form, using California pelleting machine with 1 mm diameter.

source: http://www.thefishsite.com/articles/2185/effects-of-fish-meal-substitution-with-poultry-byproduct-meal-on-juvenile-nile-tilapia/