Use of Tannery Wastes in the Diet of Broiler

Tannery waste contained 90.93% DM, 77.02% CP, 0.77% CF, 2.83% EE, 7.19% ash and 3,450 kcal ME/kg DM. A total of 144 day-old broiler chicks were divided into three dietary groups; D1 (Containing 10% protein concentrate-PC), D2 (Containing 5% PC+5% tannery waste-TW) and D3 (Containing 10% TW) having 3 replicates of 16 chicks in each. The birds were fed broiler starter diet containing 22% CP, 3,000 kcal ME/kg and broiler finisher diet containing 21% CP, 3,100 kcal ME/kg up to 42 days of age, and meat yield traits were measured from the representative birds from each replication to asses the feasibility of using tannery waste in the diet of broiler. Feed intake, live weight, feed conversion efficiency and livability did not differ between diets (p>0.05) but the cost of production and profitability differed significantly (p<0.001). Profitability of D1, D2, and D3 diets were 2.98, 9.90 and 14.04 Taka/kg respectively. Diets did not affect on meat yield traits (p>0.05), except gizzard, shank and feather weight (p<0.01). Gizzard and shank weigh were improved with increasing level of tannery wastes in the diet, hence tannery waste can be used without any harmful effect in the broiler diet. (Asian-Aust. J. Anim. Sci. 2002. Vol 15, No. 12 : 1773-1775)


INTRODUCTION
The poultry industry is gradually increasing in Bangladesh where imported costly protein concentrates are used in formulating poultry diet that increased production cost. As feed cost is about 65% of the total production cost (Singh, 1990;Banerjee, 1992). Currently poultry nutritionists are looking for cheaper inconventional energy and protein sources to formulate least cost ration. Various types of inconventional feeds (e.g. Marine Wastes, Frog Wastes, Shrimp Wastes, Rumen Ingesta, Kitchen Wastes, Banana leaf meals and Leucaena leaf meal and Tannery Wastes etc.) are available in Bangladesh, most of which are regarded as wastes and research has been done incorporating it in diets for poultry (Rahman and Reza, 1983;Islam et al., 1994).
There are 277 tanneries in Bangladesh where 240 metric tons hides and skins are processed every day. "Hazaribagh Tannery Industry" Dhaka the capital city of Bangladesh alone process 220 metric tons hides and skins a day with a total of 8.47 million liter liquid 98 metric tons solid tannery wastes produced (FAO, 1991 cited by Salam and Billah, 1998). These wastes are very potential to pollute the environment and pollute underground water through leaching which may affect human beings with cancer, skin diseases and other serious problems. Tannery wastes are used in the diet of poultry in some developed and developing countries, but no work has been done using tannery waste in poultry diet in Bangladesh. Imported protein sources like fish meal (40 Taka/kg), soybean meal (16 Taka/kg), Seasame oil cake (12 Taka/kg) and Jasoprot (protein concentrate-45 Taka/kg) were very expensive which enhance the production cost. Whereas the cost of tannery waste (collection, processing and storing cost) was 3.20 Taka/kg. Tannery waste composed of excess fat, fascia and flesh (Subcutenious tissue), unnecessary portions of the hides and skins (Trimmings) and shavings or splits materials from vegetable tanned leather. Final products of the Leather Industry are wet blue, crust and finished leather. The present study was undertaken to evaluate the value and feasibility of using tannery wastes in the diet of broiler.

MATERIALS AND METHODS
Tannery waste in the form of solid was obtained from the "Hazaribagh Tannery Industry" Dhaka, capital city of Bangladesh.

Processing and storing
Collected tannery wastes were cleaned in the fresh water to remove salt, dust or other foreign particles, and boiled at 100°C for 4-5 h. Then it was dried in the sun and ground by a grinding machine, shieved, packed and stored for 6 months in the Laboratory, Department of Animal Science, Bangladesh Agricultural University (BAU), Mymensingh.

Toxicity test
Before using this waste in the diet of broiler, aflatoxin test of the sample was performed in the Science Laboratory, Bangladesh Council of Scientific and Industrial Research, Dhaka and chromium, tannin and other heavy metals in the Laboratory of Bangladesh College of Leather Technology, Dhaka, Bangladesh. No toxicity was found in tannery waste samples.

Chemical composition
The chemical components of tannery waste taking 3 samples in each case was carried out at the Laboratory of Animal Science, BAU, Mymensingh and Bangladesh Council of Scientific and Industrial Research, Bangladesh as per method of AOAC (1990). The sample was placed in the oven at 100°C temperature for 24 h to determine the dry matter. Protein concentrate-Jasoprot imported from USA which contained 93%DM, 60%CP, 4%CF, 10%EE, 8.2%ash and 3,230 kcalME/kg.

Feeding trial
A feeding trial was performed at BAU Poultry farm for a period of 6 weeks with 144 day-old Starbro broiler chicks divided in to three dietary groups. D 1 (Diet with 10% protein concentrate-PC), D 2 (diet with 5% PC+5% tannery wastes-TW) and D 3 (diet with 10% TW) with 3 replicates of 16 chicks. Replacement of tannery waste was made on the basis of crude protein content leading to price value. Since it contained higher percentage of CP (77%) so, the replacements were made by 5 and 10% as sun dried basis. The birds were fed ad libitum a diet of 22% CP, 3,000 kcalME/kg at starter and 21% CP, 3,100 kcal ME/kg at finisher. The birds were housed with a stocking density of 0.093 sq.m./bird on rice husk littered floor providing continuous light for 24 h. The birds were vaccinated against Newcastle disease, Gumboro and infectious bronchitis and the following parameters were recorded during the experimental period: 1. Weekly body weight and feed consumption. 2. Mortality recorded daily. 3. Cost of production (Tk./kg) was calculated including feed cost, labour cost, mortality, litter, medicine, vaccine and electricity cost. 4. Profitability was calculated from the price of per kg broiler and production cost.
One male and one female broiler at 6 weeks of age in each replication was randomly selected and slaughtered to analyse the meat yield traits. Temperature and relative humidity were 33°C and 87.5%, respectively, during the experimental period.
The total time was required by one year for collection, processing, storing, toxicity test, chemical analysis of tannery waste, feeding trial and investigation of meat yield traits.

Statistical analysis
Data were subjected to MSTAT Computer package program with Least significant difference (LSD) calculated to compare between diet means.

Growth performance and profitability
Feed consumption of the chicks in the different diets; D 1 (10% Protein concentrate-PC), D 2 (5% PC+5% Tannery Wastes-TW) and D 3 (10% TW) were similar (p>0.05). Live weight, feed conversion ratio and survivability were also similar between dietary treatments (p>0.05), but production cost and profitability were different (p<0.001) (Table 1). However, feed conversion tended to be highest on diet D 2 followed by D 1 and D 3 , whereas survivability was higher on D 2 , intermediate on D 3 and lowest on D 1 . Production cost significantly decreased with the increasing level of tannery waste in the diet. Profitability was found to be highest from diet D 3 , intermediate with D 2 and lowest from diet D 1 .
The similar feed intake, body weight and feed conversion between diets in this study, supported by Koh et al. (1998), Gill et al. (1992) and Delic et al. (1982). The higher survivability from diet D 2 and D 3 to the control diet D 1 were consistent with findings of Tikhonovskaya and Snitsar, 1992. It appears that given diet D 3 showed the best profitability and survivability, followed by D 2 and D 1 with the increased tannery wastes in the diet, was in agreement with the findings of Kushak et al. (1990) and Tikhonovskaya and Snitsar (1992).

Meat yield traits
Live weight, dressing percentage, neck, breast, thigh, drumstick, heart, liver, head and blood weights were almost similar between diets (p>0.05), supported by Tikhonovskaya and Snitsar (1992). Gizzard, shank and feather weight differed (p<0.01) between diets ( Table 2). The highest percentage of gizzard and shank weight was found on diet D 3 , intermediate on D 2 and the lowest on D 1 . The highest percentage of feather was of chicken from diet D 3 followed by D 1 and D 2 . Rede et al. (1983), and Gill et al. (1992) also observed significant difference between diet containing tannery wastes.

CONCLUSION
The present investigation reveals that tannery waste is better than imported protein concentrate in respect of chemical composition, and it may be used in the diet of broiler replacing costly protein concentrate without deleterious effect. But more studies are needed on collection and processing method, toxicity and metal test, storing period, inclusion level, use in layer or ruminant, and digestibility of tannery waste to find out the potentiality of its using in the diet of poultry or livestock.