Free-range chickens are assumed to consume low to moderate levels of pasture, although the effects of forage intake in broiler performance and poultry meat quality remain to be established. In addition, despite cellulases and hemicellulases being widely used as feed supplements to improve the nutritive value of cereal-based diets for fast-growing broilers, the potential interest of these biocatalysts in the production of free-range chicken is yet to be established. In this study, broilers of the RedBro Cou Nu x RedBro M genotype were fed a cereal-based diet in portable floorless pens located either on a rainfed subterranean clover (Trifolium subterraneum) pasture or on an irrigated white clover (Trifolium repens) pasture. Control birds were maintained at the same site in identical pens but with no access to pastures. The importance of pasture intake and enzyme supplementation in the performance and meat sensory properties of the free-range chicken from d 28 to 56 was investigated. The results revealed that although cellulase and hemicellulase supplementation had no impact on broiler performance (P > 0.05), birds foraging on legume-based pastures reached significantly greater final BW. The data suggest that the improvement in broiler performance results from increased intake of the cereal-based feed rather than from an improvement in the efficiency of nutrient utilization per se. Interestingly, although the intake of the subterranean clover pasture had no impact on the tenderness, juiciness, and flavor of broiler meat, members of a 30-person consumer panel classified the meat from grazing broilers with greater scores for overall appreciation. Together, the results suggest that pasture intake promotes bird performance while contributing to the production of broiler meat with preferred sensory attributes.
Over the last centuries, Western diets acquired a dramatic imbalance in the ratio of polyunsaturated fatty acids (PUFA) to saturated fatty acids (SFA) with a concomitant reduction in the dietary proportion of n-3 PUFA. Pastures are a good source of n-3 fatty acids, although the effect of forage intake in the fatty acid profile of meat from free-range chicken remains to be evaluated. In addition, it is unknown if consumer interest in specialty poultry products derived from free-range or organic production systems is accompanied by a greater nutritional quality of these products. In this study, broilers of the RedBro Cou Nu x RedBro M genotype were fed on a cereal-based diet in portable floorless pens located either on subterranean clover (Trifolium subterraneum) or white clover (Trifolium repens) pastures. Control birds were maintained at the same site in identical pens but had no access to pasture. The capacity of ingested forage to modulate broiler meat fatty acid profiles and the meat content of total cholesterol, tocopherols, and tocotrienols was investigated in broiler chicks slaughtered at d 56. The results suggested that pasture intake (<5% DM) had a low impact on the fatty acid and vitamin E homologue profiles of meat from free-range broilers. However, breast meat from birds with free access to pasture presented lower levels of the n-6 and n-3 fatty acid precursors linoleic acid (18:2n-6) and alpha-linolenic acid (18:3n-3), respectively. In spring the levels of eicosapentaenoic acid (20:5n-3) in breast meat were significantly greater in birds consuming pastures, which suggests greater conversion of alpha-linolenic acid into eicosapentaenoic acid in these birds. Finally, when compared with meat from slower-growing genotypes obtained under the conventional European free-range production systems with slaughtering at d 81, meat from birds of the Ross genotype raised intensively and slaughtered at d 35 seemed to have greater nutritional quality.
There is an urgent need in industrialized societies to develop novel products that can lower human dietary cholesterol intake. Dehydrated alfalfa is a good source of hypocholesterolemic compounds such as saponins. Whether consumption of alfalfa by chickens would decrease the cholesterol content of broiler meat remains, however, to be established. We determined meat quality characteristics, lipid and cholesterol contents, and consumer preference of broiler meat derived from production systems based on restricted feeding of a commercial diet combined with provision of free-choice dehydrated alfalfa. Results demonstrated that it was possible to produce chicken breast meat with reduced cholesterol content. In addition, total lipids in chicken meat were significantly decreased when a higher level of restriction was applied. Members of a 50-person consumer panel preferred meat from animals not consuming or consuming moderate levels of alfalfa. Those members that preferred meat from animals consuming the higher percentage of alfalfa identified taste as the primary attribute influencing that decision. Together the results suggest that it is possible to develop novel broiler production systems that will produce leaner meat that is acceptable to consumers and has a reduced cholesterol content.
In this study, a rational combination of 200 pre-selected Carbohydrate-Active enzymes (CAZymes) and sulfatases were tested, individually or combined, according to their ability to degrade Chlorella vulgaris cell wall to access its valuable nutritional compounds. The disruption of microalgae cell walls by a four-enzyme mixture (Mix) in comparison with the control, enabled to release up to 1.21 g/L of reducing sugars (p < 0.001), led to an eight-fold increase in oligosaccharides release (p < 0.001), and reduced the fluorescence intensity by 47% after staining with Calcofluor White (p < 0.001). The Mix treatment was successful in releasing proteins (p < 0.001), some MUFA (p < 0.05), and the beneficial 18:3n-3 fatty acid (p < 0.05). Even if no variation was detected for chlorophylls (p > 0.05), total carotenoids were increased in the supernatant (p < 0.05) from the Mix treatment, relative to the control. Taken together, these results indicate that this four-enzyme Mix displays an effective capacity to degrade C. vulgaris cell wall. Thus, these enzymes may constitute a good approach to improve the bioavailability of C. vulgaris nutrients for monogastric diets, in particular, and to facilitate the cost-effective use of microalgae by the feed industry, in general.
3 November 2019 in Journal of Animal Physiology and Animal Nutrition
The main goal of this study was to test a rational combination of pre‐selected carbohydrate‐active enzymes (CAZymes) and sulphatases, individually or in combination, in order to evaluate its capacity to disrupt Arthrospira platensis cell wall, allowing the release of its valuable nutritional bioactive compounds. By the end, a two‐enzyme constituted mixture (Mix), composed by a lysozyme and a α‐amylase, was incubated with A. platensis suspension. The microalga cell wall disruption was evaluated through the amount of reducing sugars released from the cell wall complemented with the oligosaccharide profile by HPLC. An increase of the amount of reducing sugars up to 2.42 g/L in microalgae treated with the Mix relative to no treatment (p < .05), as well as a 7‐fold increase of oligosaccharides amount (p < .001), were obtained. With resort of fluorescence microscopy, a 36% reduction of fluorescence intensity (p < .001) was observed using Calcofluor White staining. In the supernatant, the Mix caused a 1.34‐fold increase in protein content (p = .018) relative to the control. Similarly, n‐6 polyunsaturated fatty acids (PUFA) (p = .007), in particular 18:2n‐6 (p = .016), monounsaturated fatty acids (MUFA) (p = .049) and chlorophyll a (p = .025) contents were higher in the supernatant of microalgae treated with the enzyme mixture in relation to the control. Taken together, these results point towards the disclosure of a novel two‐enzyme mixture able to partial degrade A. platensis cell wall, improving its nutrients bioavailability for monogastric diets with the cost‐effective advantage use of microalgae in animal feed industry.