Banca de DEFESA: ALEX STEVEN VALENCIA ORTIZ

NUTRITIONAL EVALUATION OF WORM MEAL (Eisenia andrei) AND EFFECT OF THE USE OF ZEOLITE IN DIETS 

OF NILE TILAPIA FRYINGS (Oreochromis niloticus)

Alternative foods, Aquaculture, Performance, Digestibility, Water quality

This experiment aims to evaluate the optimal level of inclusion of earthworm meal (Eisenia. Sp.) (FM) as a protein source and the effect of zeolite (clinoptilolite) on water quality, zootechnical performance, nutrient digestibility, as well as the economic viability of diets formulated in GIFT Nile tilapia fingerlings. Forty boxes of 50 liters each were used, with seven inverted tilapia fingerlings with initial and final average weight of 2,826±0,0896 g and 13.59±0.75 g, respectively. They were distributed in a 5 block design according to the initial weight and with eight treatments. The treatments were eight diets in a 4 x 2 factorial, with 4 levels of earthworm meal (0; 3.5; 7; 10.5%) and levels of 0 and 2% of zeolite. Physical-chemical analyzes were carried out: temperature (T), pH, dissolved oxygen (OD), total alkalinity (ALC), Total hardness (DT), total ammonia (AT), total toxic ammonia (ATT), total nitrite (NITRIT ) and nitrate (NITRAT). As well as water microbiology at the beginning and end of the experimental period: total coliforms (CTA) and fecal coliforms (CFA). The productive parameters evaluated were: initial weight (IP), final weight (PF), weight gain (GP), specific growth rate (TCE), Fulton condition factor (FCF), feed intake (CR), conversion apparent feed (CAA), total survival (ST), yield (RC) and carcass composition (Carcass dry matter (MSC), carcass ether extract (EEC), gross carcass energy (EBC), carcass mineral material ( MMC), carcass organic matter [MOC], carcass nitrogen (NC) and carcass crude protein (PBC)), protein retention coefficient (CRP) and energy (CRE), hepatosomatic indices (HI) and viscerosomatic index (IV ). At the end of the experiment, fecal samples were collected using the dissection method to calculate the digestibility coefficient of dry matter and nitrogen in the diets. For the feasibility analysis, the cost of feed (CTR), cost-benefit (CB), gross revenue (RB), production cost (CP), gross margin (MB), cost of consumed feed (CRC), cost of of feed per kg of live weight gained (CMR), economic efficiency index (IEE) and cost index (CI). The overall survival rate was 95.00±1.50% in the present experiment. No interaction was observed between the factors in any of the evaluated parameters. When evaluating the effect of Zeolite, it was observed that this additive had a positive influence only on water quality, as it reduced the Nitrate (p=0.0071) and CFA (p=0.0078) content in relation to treatments without zeolite. However, when evaluating the performance and carcass parameters, Zeolite did not significantly influence these results, except for CRE, which reduced (p=0.0376) in animals fed diets containing Zeolite. As for FM, it did not significantly influence when adding it to the diet in any of the evaluated parameters, except for the CRE, which linearly increased when increasing the inclusion levels of FM. When evaluating the economic viability, it shows a higher cost of diets formulated with FM, due to the market value ($US 25.05/Kg). However, it was determined that US$ 1.27/Kg would be the viable price that this ingredient should have under the experimental conditions, as they observed a non-negative effect on the IEE, IC and BC. It is concluded that earthworm meal, as well as clinoptilolite, can be used in diets for Nile tilapia at inclusion levels of 10.5% and 2%, respectively. without affecting productivity, carcass composition, diet digestibility. In addition to presenting an improvement in the microbiological quality and in the control of nitrates in the water. As for economic viability, zeolite can be added to tilapia diets, under the conditions in which the experiment was carried out, without affecting the production cost.