Due to ever increasing human population, more area is being used for cash crop and there is shortage of traditional feed items such as maize, wheat and soybean meal for poultry. This situation has necessitated using non-conventional feedstuffs as replacement for the conventional ones. Hatchery waste, when processed appropriately, has the potential to increase the viable economic profitability of the poultry production. To determine the feeding value of processed HWM, present study was conducted in four phases. In experiment I, the HWM prepared by using different processing techniques i.e., simple cooking, autoclaving and extrusion cooking was chemically and microbiologically analyzed. Proximate composition showed that the protein contents of the cooked, autoclaved and extruded HW meals were 43.67, 44.10, and 41.64%, while ash contents of meal prepared by above mentioned techniques were 25.81, 26.94 and 27.90, respectively. The high ash contents were due to presence of shell moiety. Microbial analysis of the raw HW depicted high total viable count (TVC) i.e. 8.3x107 and total coliform count (TCC) as l.9x105. Different processing techniques reduced the microbial count of HW up to a safe level. Autoclaving reduced both the TVC (4.7x103) and TCC (3.0x102) level while extrusion reduced the TVC and TCC to a level of 3.7x103 and 2.9x102, which were significantly less (P<0.05) as compared to other processing treatments.
In experiment II, protein quality of cooked, autoclaved and extruded HWM was measured in terms of protein efficiency ratio (PER) and net protein utilization (NPU). For this purpose, ten days feeding trial was conducted and five poultry rations were formulated for broiler chicks. Twenty five straight run 14-days old broiler (Hubbard) chicks were divided randomly into five groups in such a way that there were five chicks in each group. Each group was divided randomly into five experimental units in such a way that each chick represented as single replicate. The weight gain in group consuming reference diet with casein as sole source of protein showed significantly (P<0.05) higher weight gain (86.5 g) as compared to the other experimental groups. The PER values of cooked (1.46), autoclaved (1.50) and extruded HWM (1.38) were significantly less (P<0.05) than that of casein diet (1.63). The statistical analysis of data revealed that PER values of all protein sources tested, differed significantly (P<0 .05) among all groups. The minimum (1.38) PER value was observed in group fed on extruded HWM.
The NPU values of cooked (45.71), autoclaved (45.22) and extruded HWM (40.63) were also significantly less (P<0.05) than that of casein based diet (74.22). It was also observed that groups fed autoclaved and cooked HWM showed significant (P<0.05) difference with that of extruded HWM. However, there was non- significant (P>0.05) difference between autoclaved and cooked HWM with regard to NPU. The less NPU value in extruded meal was attributed to low protein contents in this meal. But overall values of PER and NPU revealed that processing of HWM can generate nutrient rich, palatable ingredients that can replace the traditional ingredients for better broiler performance.
The processed meals are rich in fat contents (18-21%) due to presence of yolk which tends to spoil the quality of NW by creating rancidity. This problem can be counter acted by addition of an appropriate antioxidant. In experiment III, cooked, autoclaved and extruded meals were stored with three different level of antioxidant. This was done to determine the optimum level of antioxidant for proper storage of meals. For this purpose, four different levels of antioxidant (Oxygun) at 0, 100, 200 and 300 mg/kg were added to the ground HWM prepared from the above mentioned processing techniques and stored for 50 days. After every 10 days, the representative samples were analyzed for peroxide value (PV), thiobarbituric acid value (TBA) and free fatty acids (FFA) contents. Variable values of oxidation were observed when the values of PV, FFA and TBA of HW treated with different processing techniques were compared at different storage periods. There was a linear increase in PV, FFA and TBA values of all the treatments. Comparison within the raw hatchery waste (RHW), cooked hatchery waste (CHW), autoclaved hatchery waste (AHW) and extruded hatchery waste (EHW) with different levels of antioxidant for PV generally showed significant differences (P<0.05) within the treatments. The PV decreased with higher level of antioxidant. This trend was observed during 50 days storage. The lowest PV was found in extruded HW with 300 mg/kg of antioxidant at 10, 20, 30, 40 and 50 days storage compared to their correspondent treatments, while highest PV was at cooked HW with 100 mg/kg of antioxidant with the same storage periods.
When different levels of antioxidant in extrusion techniques were analyzed, it revealed that extruded HW with 300 mg/kg of antioxidant was significantly (P<0.05) lower in PV as compared to extruded HW with 100 mg/kg of antioxidant. It was noted that when antioxidant level was increased in all treatments it subsequently checked the PV i.e. higher the level of antioxidant, lower was the PV. When FFA % and TBA value was analyzed it showed the same pattern as in PV.
In general, all the processing techniques as well as antioxidant addition checked the fat rancidity throughout the storage period as compared to raw samples without antioxidant addition, however synergistic effect of extrusion cooking and 300 mg/Kg of antioxidant addition was found to be most appropriate to keep the samples highly acceptable for 50 days storage period.
HW was subjected to different processing techniques and analyzed and in fourth experiment, optimum inclusion level of each type of processed HWM was determined in layer's diet. For this purpose, three hundred white leghorn hens were randomly distributed to 10 experimental diets containing 4, 8 and 12 % of cooked, autoclaved and extruded HWM respectively. Results showed that maximum egg production (79.56%) was achieved with 4 % HWM processed by autoclaving. Processing of 11W with extrusion significantly (P<0.05) reduced egg production and more pronounced decrease was found with 12 % of extruded HWM (69.48%). Egg mass and feed conversion followed the same trend, observed for egg production. Average egg weight due to different treatments fell within very narrow range and showed no difference (P>0.05) among them. Yolk, albumen and shell weights as a percentage of egg weight were not significantly affected with the use of different levels and processing of HWM. Maximum value of albumen height as well as Haugh units were obtained with the feeding of 4% autoclaved HWM. Other egg quality parameters like shell thickness, yolk index and color were independent of the dietary treatments. The findings of this study suggest that autoclaving of hatchery waste is better than extrusion and cooking techniques and 4 % of autoclaved HWM may be included in layers ration to get more production than diets without NW. Nevertheless, layer diets up to 8% HWM could be used to feed the laying hens to maintain reasonably good production without detrimental effects on egg quality.