Camelina sativa in poultry diets: opportunities and challenges

Feed represents over 65 percent of the cost for poultry production. Fast-growing and high-producing poultry are fed high calorie and high protein maize-soybean-based diets. Considering the high demand for maize and other oil crops for biofuel production, finding alternative sources of energy could reduce production costs. Camelina sativa is an oilseed crop of the Brassica family that is emerging as an important biofuel crop. Nutrient composition of camelina meal indicates that the meal has 36–40 percent crude protein, 11–12 percent fat, and 4600 Kcal/ kg gross energy. The fat in camelina meal is rich in -linolenic acid (~30 percent), the parent fatty acid of the health-promoting omega-3 family, and γ-tocopherol, an antioxidant vitamin. In addition, camelina contains other bio-active compounds such as flavonoids and phenolic products. Therefore, incorporating camelina in poultry diets will: (1) provide energy and protein to the birds, (2) provide health-promoting omega-3 fatty acids and tocopherolrich-foods to humans, (3) improve the antioxidant activity and lipid stability of poultry products, and (4) increase the market value of the crop. Feeding trials aimed at evaluating the optimum amounts of camelina meal in feed for meat-type broilers and egg laying hens were conducted. Special emphasis was given to omega-3 fatty acid and tocopherol incorporation in meat and eggs, and thus developing value-added functional poultry foods. The results obtained were: (1) camelina meal could be incorporated into broiler and layer rations at 10 percent without affecting bird performance and meat or egg quality; (2) feeding camelina meal led to over 3-fold increase in omega-3 fatty acids in chicken meat and 8-fold increase in eggs; (3) incorporation of 10 percent camelina meal led to 2.5to 3.2-fold reduction in the omega-6:omega-3 ratio in meat and eggs; and (4) inclusion of camelina meal at 5 and 10 percent led to significant reduction in lipid oxidation products and an enhancement in γ-tocopherol and antioxidant activity in the dark meat. Investigating factors that can enhance the feeding value as well as the health-promoting and antioxidant properties of camelina will provide greater potential for developing camelinabased functional feeds and value-added wholesome poultry foods for human consumption. Biofuel co-products as livestock feed – Opportunities and challenges 304 tion and other nutrient profiles of the meal can vary due to cultivar, season, processing method and other agronomic factors (e.g. soil type). The fatty acid composition of the camelina meal has received considerable attention due to its high content of essential fatty acids. The meal is rich in omega-3 and omega-6 essential fatty acids (also known as n-3 and n-6 fatty acids). The omega-6:omega-3 fatty acid ratio is 0.90 to 0.70. -Linolenic acid (18:3 n-3) is the major omega-3 fatty acid, constituting over 29 percent, with linoleic acid (18:2 n-6) constituting up to 23 percent. Oleic acid is the major mono-unsaturated fatty acid, followed by eicosenoic acid (20:1). Other mono-unsaturated fatty acids include palmitoleic (16:1) and erucic acids (22:1, <2 percent). Altogether, total mono-unsaturated fatty acid constitutes over 32 percent. Saturated fatty acids in the meal include palmitic acid (16:0, 9 percent) and stearic acid (18:0, 2.5 percent). Fat-soluble vitamin (tocopherols) content of the meal is over 200 μg/g. The protein of camelina meal contains several essential amino acids, such as threonine, glycine, methionine, valine, isoleucine, leucine, lysine and phenylalanine. Lysine and methionine are usually the firstlimiting acids in poultry nutrition, which makes camelina meal a potential source of protein for poultry. Among the minerals in camelina meal, potassium is the major mineral, followed by sulphur, phosphorus, magnesium and calcium. Camelina meal also contains other phenolic compounds and glucosinolates. The high protein, energy, omega-3 and omega-6 fatty acid and essential amino acid content of camelina meal makes it a potentially suitable source of plant protein, essential fatty acids and amino acids for use in poultry rations. FEEDING CAMELINA MEAL TO POULTRY Feed represents the major cost for food animal production. Therefore, development of non-traditional, low-cost feed sources may reduce production costs. High producing and fast growing poultry (egg layers and meat-type) are fed high calorie (2800–3200 kcal/kg/day) and high protein diets (16–22 percent crude protein). In the United States, poultry diets are based on maize and soybean meal. Considering the high demand for maize and other oil crops for biofuel production, there has been great interest in finding alternative sources of energy and protein to reduce poultry production costs. In this respect, camelina meal has attracted attention from nutritionists due to its gross energy and crude protein content. Recently, studies were conducted with meat-type broiler chickens, egg layers or turkeys on feeding camelina meal, and results are summarized in Table 2. These studies were aimed at (1) finding the optimum levels that can be incorporated into the ration without affecting production performances, (2) assessing product quality, and (3) testing the efficacy of camelina meal in enriching the meat or eggs with omega-3 fatty acids. Effect on production performance of feeding Camelina sativa meal to broiler chickens The effect of feeding camelina meal to broiler birds led to conflicting results in growth performance (Table 2). Aziza, Quezada and Cherian (2010a) fed 2.5, 5 and 10 percent camelina meal to broiler birds and these authors reported no difference in 42-day body weight gain, carcass weight or feed efficiency (gain:weight) when compared with maizesoybean-based control diet-fed birds. However, Ryhanen et al. (2007) and Pekel et al. (2009) reported that feeding 10 percent camelina meal or expeller cake to broiler chickens impaired the growth between 15 and 37 days of age, decreased feed intake during the starter phase, impaired feed efficiency and reduced the final body weight by 7–10 percent compared with the control group. Studies on feeding camelina meal to turkey hens by Frame, and Petersen (2007) reported no significant differences in final weight, weight gain or feed conversion when 10 percent camelina meal was included in the diet from 9 weeks through to 13.5 weeks of age. The discrepancies in growth performance of birds fed diets containing camelina meal • Camelina meal is rich in protein, fat and essential n-3 and n-6 fatty acids, and could be incorporated into poultry rations as a source of energy, protein and essential n-3 and n-6 fatty acids. • Feeding camelina meal up to 10 percent of the diet did not affect growth performance and feed consumption, nor meat and egg quality. • Feeding 10 percent camelina meal led to increases in health-promoting omega-3 fatty acids of over 3-fold in chicken meat and 8-fold eggs. • Camelina meal at 10 percent led to significant reduction in lipid oxidation products and an improvement in antioxidant activity in the dark meat. • Consuming two large eggs from hens fed 10 percent camelina meal could provide over 300 mg omega-3 fatty acids to the average human diet. MAIN MESSAGES Camelina sativa in poultry diets: opportunities and challengesy 305 could be due to the availability of nutrients in the meal. Camelina belongs to the Brassica family, which is high in non-starch polysaccharides and glucosinolates that can affect feed consumption and growth performance of broiler chickens (Budin, Breene and Putnam, 1995). In addition, phenolic compounds such as phenolic acids and tannins that are present in the Brassica family, soil type, bird age and meal preparation methods can affect digestibility, leading to discrepancies in reported results. Pekel et al. (2009) reported that addition of copper (150 mg/kg) enhanced feed consumption and body weight of birds fed camelina meal. The beneficial effect of Cu may be due to its ability to alleviate the negative effects of glucosinolates present in the meal. Although glucosinolates themselves show no toxic effects on animals, the breakdown products of glucosinolates can form toxins by the endogenous plant enzyme myrosinase or can influence gut microflora, affecting growth and feed efficiency (Schuster and Friedt, 1998). These factors should be taken into consideration when evaluating results from feeding camelina meal to broiler birds. Effect on production performance of feeding Camelina sativa meal to egg laying hens Oil seeds and oilseed meals are incorporated into laying hen rations as a source of energy, crude protein and essential omega-3 fatty acids. In this respect, much work on feeding flax seed to laying birds for omega-3 egg production has been well documented (Cherian, 2008). Typically, oil seeds or their meals are restricted to less than 10 percent of the rations (Bean and Leeson, 2003). Lipid quantity and type of fatty acids in oil seeds in the laying hen diet can significantly affect the content of fatty acids, fat soluble vitamins and pigments in the egg yolk. The alteration of egg lipid nutrient profile is due to the fact that chickens are monogastric (single stomach) animals and that there is a high turnover of lipids in laying hens, causing egg lipid to mirror dietary fats. This has led to the successful production and marketing of omega-3 fatty acidand vitamin-modified specialty eggs worldwide (Cherian, 2009). Considering the high content of -linolenic acid in camelina meal, studies were conducted to test the efficacy of the meal in enriching eggs with omega-3 fatty acids. Feeding trials conducted in our laboratory showed that inclusion of camelina meal at over 10 percent of the ration can affect egg production, feed consumption and egg yolk weight. When the meal was included at 5, 10 and 15 percent of the ration, it was observed that hen-day egg production ([total number of eggs produced/total number of hens × number of days on test diet] × 100), was lowest for the 15 percent inclusion level (Cherian, Campbell and Parker, 2009) (Table 2). Yolk weight as a percentage of egg weight was lower for the 10 and 15 percent inclusion levels. However, decrease in TABLE 1 The nutrient profile of camelina meal