Dr Sonali Prusty
Assistant professor, Department of Animal Nutrition, College of Veterinary Science and A.H., Anjora, DSVCKV, Durg
Introduction
Poultry farming is the fastest-growing sectors of animal husbandry. In commercial poultry production, feed accounts for nearly 65–75% of recurring costs in broilers and 75–80% in layers. Traditionally, poultry diets have depended heavily on yellow maize for energy and soybean meal and fishmeal for protein.This conventional feeding system, however, is facing growing economic and environmental challenges. Maize has long been the standard energy source in poultry diets. It provides around 3350 kcal metabolizable energy/kg, 9.3% crude protein and 70.3% nitrogen-free extract. But depending almost entirely on maize can make poultry production vulnerable to fluctuations in availability, price and climate.
Alternate energy source
Sorghum, or jowar, is particularly attractive because it can tolerate relatively harsh and drought-prone conditions. It provides about 2,593 kcal ME/kg, 10.5% crude protein and 5.6% crude fibre.Its major limitation is tannin, which can interfere with protein digestion and reduce poultry performance. Low-tannin sorghum, however, can be incorporated at considerably higher levels. With proper variety selection and balanced diets, sorghum can replace a substantial proportion of maize in broiler diets.
Pearl millet(Bajra) is another promising climate-resilient cereal. With approximately 12.8% crude protein and 2,655 kcal ME/kg, it can be incorporated at substantial levels in poultry diets.Feeding pearl millet to laying hens has been associated with eggs containing higher levels of desirable fatty acids, including omega-3 fatty acids. This opens the possibility of producing value-added or “designer” eggs through strategic feeding.
Rice milling generates considerable quantities of broken rice. Instead of allowing this material to remain underutilized, it can serve as a valuable energy source in poultry diets.Broken rice contains approximately 4,060 kcal gross energy/kg and can be incorporated into broiler diets.
Alternate protein source
Protein is another major challenge in poultry nutrition. Soybean meal has traditionally dominated poultry diets, but increasing demand and environmental concerns have encouraged scientists to explore alternative protein sources.
Guar meal is a by-product of guar gum production and contains approximately 40–48% crude protein. Its use is limited by compounds such as galactomannans and trypsin inhibitors, which can increase intestinal viscosity and interfere with nutrient utilization.Through enzyme supplementation or microbial fermentation, the safe inclusion level of guar meal can be increased.
The biofuel and rice-processing industries also generate valuable protein-rich co-products like DDGS and Rice Gluten Meal. Rice DDGS contains approximately 45% crude protein, while rice gluten meal can contain nearly 58% crude protein.
Plants such as moringa and Azolla are also attracting attention.Moringa leaves are rich in protein and carotenoids and can be incorporated into poultry diets at appropriate levels. Besides supporting production, moringa can contribute to improved egg weight and yolk colour.Azolla, a fast-growing aquatic fern, contains approximately 24.5% crude protein on a dry matter basis. Its inclusion in poultry diets has shown potential, particularly as a supplementary feed resource.
Chickens naturally consume insects when they forage. Insect meal is emerging as one of the most interesting alternative protein sources. Dried insect biomass can contain approximately 40–60% crude protein and 30–40% crude fat, along with useful fatty acids and bioactive compounds.Promising species include the black soldier fly, housefly, yellow mealworm, earthworms and silkworm pupae. Spent silkworm pupae, for example, can contain nearly 49% protein and 30% fat.The environmental advantage is equally important. Insects can be produced using organic side-streams while requiring considerably fewer resources than many conventional animal-protein sources.Replacing some or all of the fishmeal in poultry diets with suitable insect meals can maintain or even improve nutrient utilization and poultry performance, while potentially reducing greenhouse-gas emissions, water consumption and aquatic pollution.
Strategies for improvement in utilization of feed
Alternative feed ingredients often contain compounds that poultry cannot digest efficiently. One major group is non-starch polysaccharides (NSPs).Wheat, rye and triticale contain arabinoxylans, while barley and oats contain β-glucans. These compounds can absorb water and increase the viscosity of intestinal contents. The result is slower digestion, poorer nutrient absorption and wetter litter.Enzymes such as xylanase, β-glucanase and cellulase help break down plant cell-wall components and release nutrients trapped within them. Proper enzyme supplementation can improve nutrient availability and overall dry matter digestibility.Another important enzyme is phytase. A large proportion—around 60–90%—of phosphorus in plant ingredients is bound in phytate. Poultry cannot efficiently utilize this phosphorus without enzymatic assistance.Phytase breaks down phytate and releases phosphorus along with other bound nutrients such as calcium, zinc and amino acids. This can reduce dependence on inorganic mineral supplementation and, importantly, lower phosphorus excretion into the environment.
The search for alternatives to antibiotic growth promoters has also brought plant-based feed additives into use. Herbs, spices and essential oils contain biologically active compounds that can influence digestion, immunity and intestinal health. Compounds such as thymol, carvacrol, cinnamaldehyde, eugenol, capsaicin and piperine have shown antimicrobial and digestive-supporting effects.These compounds can help control undesirable intestinal microorganisms such as Clostridium perfringens and Escherichia coli. They may also stimulate digestive secretions, improve intestinal morphology and support the overall health of the gut.Plants such as Cassia tora have also been investigated as natural growth-promoting alternatives. Their bioactive compounds may influence immune responses and blood biochemical parameters while exhibiting antibacterial activity.
Feeding to combat heat stress
When temperatures rise, birds reduce feed intake, alter their metabolism and begin panting to lose body heat. These changes can seriously affect growth, egg production and feed efficiency.Simple nutritional and management strategies can help.Feed can be offered during the cooler parts of the day, particularly early morning and late evening. Pelleted diets or appropriately prepared wet mash can reduce eating effort and encourage feed consumption.Electrolyte management is also important. Sodium bicarbonate, ammonium chloride or potassium chloride can be used appropriately to help maintain acid–base balance.Antioxidant nutrients such as vitamins C and E, together with appropriate selenium supplementation, can provide additional support during heat stress.
Conclusion
Sustainable feeding is not simply about finding cheaper ingredients. It is also about feeding the right nutrients in the right amounts. Modern poultry diets should increasingly be formulated according to digestible amino acid requirements, rather than relying solely on total crude protein. Supplementation with amino acids such as lysine, methionine and threonine allows diets to be formulated more precisely. This can reduce unnecessary dietary protein and, consequently, reduce the amount of nitrogen that birds must excrete.