Toxicity, Nutritional Quality, and Microbial Loads of Source-Separated Dried Food Waste as Poultry Feed
摘要
On a global scale, a third of food prepared, manufactured and distributed is wasted. This costs the global economy $2.6 trillion annually. In Ghana, daily, 20 tonnes of waste is sent to the landfill. Food waste comprises 60%. This study aims to depict how food waste generated from sources can be collected, heat-treated and included in poultry feed diets confirming its potential with sensory and market analysis. Two heat treatment alternatives (oven vs rotary drying) were incorporated into food waste treatment to ascertain which is more economical and efficient. Food waste collected was categorised into Cereals & Grains (CW), Roots and Tuber (R&T) and Vegetable (VW). The general feed formulation of FW was 50% CW, 40% R&T and 10% VW. A total number of 250 Ross broilers were assigned five treatments in a completely randomised design for 7 weeks. Treatments design consisted of control (T1), 50% FW (T2), 50% FW with 2% soybean oil (T3), 100% FW (T4) and 100% FW with 3% soybean oil (T5). The remaining portions of the diet ratios were a standardised poultry diet formulated on most Ghanaian poultry farms (maize, wheat bran, oysters, soybean, fish meal, calcium). Data were analysed using one-way analysis of variance (ANOVA) using the generalized linear model procedure of SAS Statistical software. A comparison of means was performed using the Tukey's Studentized Range (HSD) test at a probability of 5%. The dehydrated food waste had 8.49% - 14.538%, 2.85% - 16.42% crude protein, fat 0.35% - 1.45% and fibre of 20.3% -30.96% respectively and average metabolizable energy of 2421.67 kcal/kg. The results indicate the treatment group, T2 (50%FW) had the highest body weight with 2743.32 g. The next treatment by body weight was a FW diet with 50% maize as well however inclusive of soybean oil (T3) with a body weight of 2361.53 g. Corresponding with body weight and FCR (1.76), feed intake of T2 was 3.39 kg. Subsequent treatments (T1, T3 and T5) conformed to this positive relationship except for T4 which had a poor FCR of 2.3 despite a high feed intake of 2.9 kg. Abdominal fat was within the expected range of 17.75 g—33 g with the highest amount of fat being 50% FW with 2% soybean oil as expected. Internal and visceral organs were discovered to be within range, indicating a level of good health amongst birds. Haematological parameters of WBC, RBC, HCT were in low levels, suggestive of anaemic conditions yet to manifest. The microbial analysis confirmed the presence of bacteria and fungi active on feed, indicating feed to be of lesser quality. Toxicological analysis did not bear much influence on growth performance due to their minute amounts. Sensory analysis performed by 10 participants resulted in food waste inclusion meat dry matter 50% FW being selected as the overall best.