Utilization of animal by-products for incorporation in poultry feeds as a source of animal protein
D.V. R. PRAKASH RAO
Feed resource is a major constraint confronting the Poultry industry. The unprecedented demand for cereals and protein sources are escalating the feed cost threatening the poultry industry to run on razor blade margins. Thus the poultry producers and Nutritionists are constantly facing new challenges in poultry production.
The purpose of intensive poultry production is to maximize the financial returns. This cannot be achieved unless the biological responses to the given inputs are known and the input output relationship is financially measured. Diets designed to maximize egg production or weight gains are not necessarily those that will result in maximum financial returns. Thus devising optimum feed strategies for maximized financial returns is highly essential for a viable poultry enterprise.
The recycling of animal by products into animal protein is a most modern concept of replacing conventional animal protein sources in diet for poultry. The animal protein is a critical nutrient requirement in the manufacture of poultry feed since they are good sources of essential amino acids.
India is emerging as a largest and fastest growing consumer market in the world due to the dramatic changes in the economic environment and liberalization of Indian economy. The progressively effluent middle class of about 300 million people have increased the consumption of meat and meat products which has resulted in the availability of large quantity of meat offals from the slaughter house.
There are about 4600 authorised slaughter houses in the country where 14.97 million cattle, 12.31 million buffaloes, 26.14 million sheep and 78.8 million goats are slaughtered in the existing slaughter houses in addition to the illegal and unorganised slaughter (1996). It is estimated that around 3.0 million tons of meat offal is generated per annum in different parts of the country, posing a great ecological challenge.
The manufacturing technology to be adopted should be a possible combination of heat, pressure and moisture without any loss of crude protein or amino acids in the final product. Many advantages are claimed for a proper processing technology, which increases the availability of protein and energy and destroys the anti nutritive factors.
Rendering is a process of recovering fat and protein from animal offal. The operation consists of heating animal offal to a temperature at which the cells disrupt releasing the fat that melts and also coagulate the protein. Meat is composed of 3 protein fractions, viz., Sarcoplasmic, myofibrillar and tissue types. The Sarcoplasmic proteins are soluble in their native form but the other two proteins have insoluble structure. The hydrolysis during rendering process contributes to the breaking down of these proteins.
The working pressure, meat particle size and processing time are important controlling parameters. Thermal process plays an important role in achieving optimum process conditions. The large thermal driving force between the rendering vessel jacket and the meat mass is an essential factor. Application of moderate vacuum in conjunction with steam heating or higher steam pressure in the jacket will enhance the driving force. The agitation of meat mass contributes to efficient heat transfer inside the mass.
Rendering technology is classified as wet and dry rendering. In wet rendering, the raw material is cooked by direct contact steam whereas in dry rendering the steam will be circulating in double jacketted stainless steel vessel and does not come in direct contact with raw material. Here, the raw material is cooked indirectly by the steam which is circulating in the outside jacket thus ensuring better sterilization due to higher temperature and pressure. It also ensures that the nutrient values are not disturbed.
Thus the Meat and Bone Meal manufactured with dry rendering technology shall be free from all pathogenic micro organisms, such as E coli, Salmonella and Clostridium. The normal recommended temperature for complete sterilization is 135˚ C under 3 bar pressure which will destroy even the prisons.
Crude Protein% 48 - 55
Crude Fat% 5 - 8
Calcium% 6 - 10
Phosphorous% 3.5 - 5
Lysine% 2.5 - 3.0
Meth + Cystine% 1.07 - 1.15
M.E. Value – 2000 – 2100 kcal/kg.
METHODS OF EVALUATION OF QUALITY OF MEAT AND BONE MEAL:
Many methods have been proposed for assessing protein quality of animal protein meal. They can be divided into In vitro and In vivo. The in vivo assays involve actual measurements in the live animals and hence are difficult. The In vitro is used mostly in the chemical laboratory which are fairly good predictors of protein quality. The Pepsin Digestibility assay is useful by using a pepsin concentration of 0.2%. The nitrogen digestibility values for MBM decrease as the pepsin concentration is reduced from 0.2 to 0.002%.
The KOH protein solubility tests have been shown to be a good indicator of Protein quality for the oil seed meals. But KOH values for Meat and Bone Meal could not be co-related with any in vivo protein quality measurements. Thus KOH solubility tests do not indicate protein quality for Meat and Bone Meal. A potentially very useful in vitro method is near infrared reflectance spectroscopy (NIRS) for predicting the digestibility of MBM in poultry (Vankempen and Jacuson, 1996).
Thus Meat and Bone Meal provides an ideal combination of protein and phosphorous to help the farmer to reduce the cost of feed at least by Rs. 200/- per tonne at the same time improving the feed conversion ratio.
|Source : IPSACON-2005|