科研之友
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摘要
Palm oil and its derivatives play a significant role in animal nutrition, and the opportunity to increase usage in this sector is large. Fats and oils are used as energy sources, to supply dietary essential fatty acids (linoleic and linolenic acids) that cannot be synthesized by the animal, to aid in the absorption of fat-soluble vitamins, and to provide specific bio-active fatty acids. The amount of fat or oil that can be used in animal diets varies depending on the species and its digestive physiology. The digestive systems of cattle, pigs and poultry differ with respect to the way in which fats/oils are broken down, absorbed and utilized. Cattle are ruminants in which the fermentation of carbohydrates in the rumen provides energy for the animal. Dietary triglycerides are largely hydrolyzed in the rumen by the resident microbial population, while the unsaturated fatty acids are hydrogenated to saturated fatty acids. Feeding large amounts of triglycerides (>3% of the diet), particularly those which are unsaturated, inhibits rumen microorganisms and makes biohydrogenation incomplete. If biohydrogenation does not occur fully, a flow of unsaturated or partially unsaturated fats/oils with trans-double bonds into the small intestine can decrease feed intake and depress milk fat production, as well as alter milk fat profiles. To overcome this problem, fats/oils for ruminant feeding need to be in a form that makes them inert in the rumen, such as in the form of a calcium salt or soap of palm fatty acid distillates (CaPFAD), or after crystallizing the saturated fatty acids by beading or flaking. Pigs and poultry are non-ruminants (monogastrics) and rely on their own enzymes for the breakdown of dietary triglycerides. Fatty acids are then absorbed in the small intestine along with mono- or diglycerides. Pigs and poultry can utilize relatively saturated as well as unsaturated fats in their diet, but the inclusion of unsaturated fats/oils results in more unsaturated fatty acids in their body fat, which makes the carcass fat softer and this can reduce carcass quality. Increased energy levels in the diet of dairy cows can benefit the production of milk and milk components, improve reproductive efficiency, reduce heat stress, and improve general health and well-being. Increasing fat/oil levels in pig diets improve growth rates, reproduction and lactation. Hard (more saturated) dietary lipids help produce firmer carcass fat. Increasing fat/oil levels in poultry diets improves feed efficiency and growth rates. Medium-chain triglycerides (MCTs) are also of interest, particularly in young animals where their rapid absorption can help provide a readily available energy supply. Palm oil and palm kernel oil can be used to replace butterfat in milk replacers for feeding young animals to substitute their mother's milk. Fats are also used in the diets of companion animals (dogs and cats) and horses. Worldwide animal production is increasing rapidly. As standards of living increase, more animal products are being consumed in the diet, including meat, milk and eggs. Livestock consume approximately 33% of global cereal grain production, and the animal nutrition industry consumes between 8 and 10 million tonnes of fats and oils per annum. This use will increase significantly in the next 15 years as more animal products are consumed. In addition, there is greater focus on finding ways to replace cereal energy in animal nutrition as cereals are increasingly being diverted to human foods or biofuel production.
Fat/oil levels in feed are generally lower than the leels that can be utilized by the animal based on its digestive and metabolic processes. More calories could be supplied by fats/oils but there are limitations based on the physical characteristics of the fats and oils and their interactions with the target animal's physiology.
- 出版日期2010-12
