Preparation and nutritional evaluation of poultry farm litter and dead birds compost for use in poultry feed

Abstract

The poultry industry produces large amount of wastes, including poultry litter, manure, and dead birds, requiring regular and prompt disposal during the course of a normal production cycle. Disposal by burial, incineration, landfills, rendering, on-farm freezers, or other preservation techniques is not adequate and may have serious implications for animal, poultry, and human health. Poultry farmers need a convenient, environmentally acceptable, and bio-secure way of disposing poultry carcasses. A potentially efficient and cost-effective option for the disposal of poultry waste (litter, dead birds) is to recycle the waste as a feedstuff for use in poultry feed, which could be possible through proper composting of the litter and dead birds, and optimized feed management practices. The utilization of dead hens and rendered spent hens as a feed source is well documented in the literature, but, to our knowledge, no literature exists regarding the use of compost in poultry feed. It was hypothesized that including compost in poultry diets at levels up to 10% could produce similar performance gains as diets without compost while being more cost-effective. Thus, this study was planned to explore the effect of including compost in the diet on performance, blood biochemical profile, and immune antibody response of commercial broilers, quail broilers, and commercial layers. The study was executed in two phases. In phase I, litter and dead bird compost was prepared and chemically analyzed. In phase II, three biological trials were conducted to assess the feeding values of compost for commercial broilers (experiment 1), quail broilers (experiment 2), and commercial layers (experiment 3). In experiment 1, a total of 300 day-old broiler chicks (Cobb-500) were randomly distributed to five treatment groups. Each treatment group contained 10 birds and experiments were replicated six times using a completely randomized design (CRD). In experiment 2, a total of 1200 newly hatched quail chicks (Coturnix coturnix japonica) were distributed to five treatment groups. Each treatment group contained 40 birds and experiments were replicated six times using a CRD. In experiment 3, a total of 150 laying hens (Novogen White, 18-week-old) were distributed to five treatment groups. Each treatment group contained six hens and experiments were replicated five times. The experimental diets consisted of increasing levels of compost (0, 2.5, 5, 7.5, and 10%), but were otherwise iso-caloric and iso-nitrogenous. Data were analyzed by one-way ANOVA under CRD. In experiment 1, there were no differences (P>0.05) in feed intake, live weight gain, feed efficiency, and mortality for birds fed compost at any level compared to birds fed the control diet. Carcass yield and relative weights of breast, thigh, wing, liver, gizzard, and heart were not affected (P>0.05) by the compost supplement to the diet; however, the highest level of compost (10%) caused a marked decrease (P=0.028) in abdominal fat content compared to control and 2.5% compost diets. Similarly, there were no differences (P>0.05) in sensory grading, compositional profile, serum biochemical indices, and immune-related parameters in birds fed the different diets. Birds fed the 10% compost diet, however, showed the lowest (P=0.0001) feed cost per kg weight gain compared to those fed the control diet. Similarly, in experiment 2, feed intake, live weight gain, feed efficiency, and mortality for birds given the compost supplemented diet was comparable (P>0.05) to that of birds fed the control diet. Carcass yield and relative weights of breast, thigh, wing, liver, gizzard, heart, and abdominal fat were not significantly different across treatments (P>0.05). Although, a slight reduction in breast and thigh weights was observed in chicks fed compost at 10% level compared to control chicks, but statistically this difference was not significant (P>0.05). Similarly, no differences (P>0.05) in sensory properties, compositional profile, serum biochemical indices, and immune-related parameters were observed among the diets. The experimental group fed compost at 10% showed the lowest (P=0.0001) feed cost per kg weight gain compared to control group. In experiment 3, hen performance parameters, including average daily feed consumption, final body weight, egg production, egg weight, cumulative egg mass, feed efficiency values, livability, and uniformity percentage, were not affected (P>0.05) by the addition of compost to the diet at any level. Although, hens fed the diet containing 10% compost exhibited slightly lower egg production and egg weight compared to control hens, but statistically this difference was not significant (P>0.05). Similarly, there were no differences (P>0.05) in egg quality, yolk fatty acid composition, egg sensory characteristics, serum biochemical profile, and immune-related parameters among the diets. Finally, the lowest (P=0.0001) feed cost per kg egg mass was observed in the hens fed diets containing compost 10% compared to control hens. Taken together, these data indicate that compost can be utilized in diets for commercial broiler, quail broiler, and commercial layer up to 10% without compromising performance, blood biochemical profile, and immune antibody response. Furthermore, the utilization of compost as a feed resource may reduce feed cost per kg live weight gain and feed cost per kg egg mass