Sachin Tripura1, Mitek Tarang2
1Ph.D. scholar, Division of Animal Nutrition, ICAR-National Dairy Research Institute, Karnal, Haryana
2Ph.D. scholar, Division of Animal Genetics and Breeding, ICAR-Indian Veterinary Research Institute, Izzatnagar, Uttar Pradesh
Introduction:
Increased feed grain prices and production costs and the potential for depletion of feed grain inventories due to increased demand are major concerns for producers in the pork industry. Feeding of pigs is the single most expensive aspect of pork production. As a result, feed costs play a major role in determining the profitability of a swine enterprise. Grains such as maize, wheat, sorghum and oats have traditionally supplied energy. Price relationships between traditional and alternative feed ingredients vary greatly depending on the season, availability and global and local markets. Pork producers must be able to evaluate the cost effectiveness and nutritional value of all available feed ingredients to supply a nutritionally balanced diet at a minimal cost. Many alternative feeds that may be cost effective and useful in swine diets are produced by the industries involved in grain milling, brewing, distilling, fruit and vegetable processing and vegetable oil refining. Many of the by-products from these processes can readily substitute a portion of the energy in a complete feed. The appropriate amount to use will depend on the cost, nutrient availability, palatability, presence of anti-nutritional factors, storage life and age of the pig for which the feed is intended.
Energy in swine nutrition and its importance:
Energy is one of the most expensive components of a practical pig diet. The energy enclosed in the feed as chemical energy is released by partial or complete oxidation following digestive and absorptive mechanisms in the gastrointestinal tract. The energy supplied through diets is utilized by the animal for two main functions; maintenance and production. Maintenance functions includes basal metabolism and involuntary activities such as muscle tone, feed digestion, blood circulation, tissues replacement, maintenance of membrane potential and acid-base homeostasis along with breaking down of complex chemical substances into simpler form that can be eliminated as waste products from the body. In addition, energy is also necessary to maintain the body temperature irrespective of the environment in which the pig is placed, which is otherwise known as the homeothermal functions.
Why search for alternate energy sources?
As the world population increases there is a stiff competition for grain between humans and animals. Humans use grains for ethanol and energy production while animals use this resource as a feed source. Feed costs accounts for most of the production costs in almost any animal production system but in the pig industry, this cost is as high as 70-75%. This situation is partly the result of competition between man and livestock for some food and feed ingredients, particularly, energy sources, such as maize. It would therefore be economically convenient to explore the use of alternative feedstuffs such as non-conventional feed resources or agro-industrial by-products, which are abundant, cheap and rich in energy content.
Alternate energy sources:
The alternate feed ingredients which can be used as energy sources in swine feeding are as follows-
Barley
Palm kernel cake
Cassava root silage
Canola meal
Distillers dried grains with soluble
Brewers’ spent grains
Fats & oils
Barley:
Barley contains more lysine than corn but it contains less energy and more fiber. Therefore, pigs fed barley based diets will tend to have 5 to 10% poorer feed efficiency. Fine grinding of barley diets improves the feeding value for growing/finishing pigs since feed intake is usually not a limiting factor. Even though the barley based diets are lower in energy than corn based diets, pigs are able to compensate by eating more. They will simply eat enough to meet their energy requirements. Therefore, producers may find it advantageous to use barley in combination with higher energy grains, such as corn or wheat. Barley can also be used as the sole cereal grain in sow diets during gestation. However, low energy density suggests limiting the use of barley to 85% of the cereal grain in lactating sow and 25% in weanling pig diets unless it is pelleted. Inclusion of barley grain in starter pig diets is limited due to its high fiber content that is associated with lower nutrient digestibility and NE value than corn.
Palm kernel cake:
Palm kernel cake is a byproduct of oil extraction from palm nut and it is abundant in the tropical areas of the world. It is an excellent feed ingredient for animal production due to its availability and low cost. The proximate analysis has showed that it can be classified as energy feed, with the chemical component, very similar to that of corn gluten or rice bran. Its earlier use as feed ingredient was mainly for ruminants because of its fibrous nature (16-18% and above), low palatability and low availability of amino acids and energy, hence considered unsuitable for non-ruminants if included at high levels in poultry or pig diets. Improving the nutritive value of palm kernel cake for mono-gastric animals may therefore require supplementation with a more digestible ingredient, such as cassava flour or meal.
Cassava root silage:
Cassava is an annual tuber crop grown widely in tropical and sub-tropical area and its tuberous root is the most important portion of the plant and can be used as raw material in various industrial derivatives. Cassava is used in food, especially in the form of flour and starch. In animal feed, it is used as energy source, because it is very rich in starch. Cassava roots have favorable characteristics for silage because they have 62-68% of moisture and easily fermentable carbohydrates. As silage, cassava roots have high amount of dry matter, crude protein, crude fiber, ash and less fat compared with fresh roots. Considering the high nutritional value of cassava, as well as their usage limitations in animal feed, particularly related to the difficulty of conservation, it is important to carry out processing forms to make them usable in swine diets.
Distillers dried grains with soluble (DDGS):
It is produced from the fuel ethanol industry and is available for inclusion in diets of swine. The average concentration of gross energy in DDGS is approximately 5,530 kcal GE per kg dry matter (DM). Diets designed to contain DDGS should be formulated on the basis of digestible amino acids and digestible phosphorus. In general, 10% DDGS can replace approximately 4.25% soybean meal and 5.70% corn, if 0.10% crystalline lysine is included in the diet. DDGS can be included in diets of nursery pigs, growing finishing pigs and sows in amounts of 20% and in diets for gestating sows at 40%. At these inclusion rates, excellent performance of pigs has been reported provided that diets are formulated on the basis of digestible amino acids. Greater inclusion rates are possible, but may not always maximize pig performance.
Fats and oils:
Fats and oils contain about 2.25 times more metabolizable energy per unit of weight compared to carbohydrates in cereal grains. Fats are available commercially in products such as choice white grease, bleachable fancy tallow, prime tallow, yellow grease, hydrogenated vegetable fat, corn oil, soybean oil and various dry fat products. Fat sources should be protected from rancidity by an antioxidant. Certain biological effects can also be expected when fat is added to diets of starting, growing, and finishing pigs. These include: improved palatability, reduced feed consumption and improved feed efficiency due to the increased energy density, a slight increase in growth rate, and increased carcass fatness at high fat levels. Fat changes the physical characteristics of a swine feed, reduces dustiness, and improves the air quality in swine buildings. When fat is added to a swine diet, the amount of feed consumed usually decreases. However, the requirement of the pig for other nutrients remains relatively constant when expressed on a daily basis. Therefore, to maintain performance when fat is added to the diet, the concentration of other nutrients should be increased. The decision to add fat is largely based on economics. If the value of the improvement in growing finishing feed conversion is greater than the cost of adding fat, it is economical to use. Typically, adding 1% fat to the diet results in approximately 2% improvement in feed conversion. Fat is often added to the diet of early grower and lactation diets because energy intake is often limiting to support maximal performance.
Factors affecting the inclusion rate of alternate energy feed resources:
• Cost of the ingredients
• Relative value
• Energy & nutrient digestibility
• Anti – nutritional factors
• Palatability
• Moisture content
• Fiber content
• Nutrient variability
• Stability of nutrients
Conclusion:
Feed accounts for 70-75% of cost of pig production and alternative feed sources are keys to making the production systems a profitable one both in the economic and financial departments. Cash crops are mainly used as energy source in swine and other livestock ration. There is a huge reduction in availability of feed resources for livestock and the cost of ingredients is increasing day by day. Due to urbanization and reduction of land availability for cash crop cultivation, alternate feed resources are the need of the hour. Diets containing palm kernel cake, cassava root silage, canola meal, distillers dried grain soluble may be fed to pigs without reducing performance of the animals. These energy rich by-products can be utilized effectively as swine feed to reduce the cost of production. However, it is always important to monitor the nutritional quality of the ingredients and diets containing these ingredients need to be carefully formulated to make sure that all nutrient needs of the animals are met.
