Profitability and meat quality of fast-, medium- and slow-growing meat-type chicken genotypes as affected by growth and length of rearing.

The study aimed to evaluate the profitability, meat quality, and carcass parameters of fast-, medium-, and slow-growing meat-type chicken genotypes of Bangladesh. Nine hundred DOCs were randomly allocated to 6 treatments: T1 = commercial broilers, T2 = CPF-3 (central poultry farm-3), T3 = cockerel, T4 = sonali, T5 = NDD (non-descriptive desi), and T6 = hilly, having 5 replications of 30 chicks each. Birds were reared under complete confinement until their respective market ages (commercial broilers = 35 d; CPF-3 = 45 d; cockerel = 56 d, and hilly = 77 d; sonali = 63 d and NDD = 77 d) and fed commercial broiler diets. Net returns, meat quality, growth, and carcass yield were measured. NDD and hilly showed significantly the highest profitability and superior meat quality. Commercial broilers exhibited the highest final body weight (2355.59 g/b) followed by hilly (1241 g/b) and NDD (1006 g/b), while CPF-3 (860.21 g/b), cockerel (915.49 g/b), and sonali (788.43 g/b) had lower final body weights at their respective market ages. Commercial broilers had the highest carcass weight and dressing yields, followed by hilly and cockerel, and lower in sonali, CPF-3, and NDD. The study concluded that rearing slow- or medium-growing NDD and hilly is superior to fast-growing commercial broilers or CPF-3 regarding profitability, and meat quality. The results of current findings help small-scale farmers in choosing a suitable meat-type chicken that yields better profitability and also for the consumers who wish to pay a fair price for the birds, considering the meat quality specific to each chicken genotype.

Bitter Taste Receptor Antagonists Inhibit the Bitter taste of Canola Meal Extract in Chickens.

Canola meal (CM) is a commonly used feedstuff; however, it is known to be bitter, and chickens have a low preference for it. The purpose of this study was to seek clarity regarding the taste quality of CM and find methods to increase the preference for CM by chickens. We examined whether CM activates the bitter taste receptors in chickens, whether chickens show aversive responses to CM, and whether an antagonist for bitter taste receptors inhibits the bitterness of CM. Using the Ca2+ imaging technique, we showed that CM contains bitter compounds, which activate the bitter taste receptors in chickens. Further, we showed that 6-methoxyflavanone (6-meth), an antagonist for the bitter taste receptors in chickens, inhibits the activation of these receptors by CM extract. Although chickens showed a low preference for the solution of the CM extract, their preference was improved by adding 6-meth in behavioral tests. These results suggest that the preference for CM could be improved by inhibiting the bitter taste receptors in chickens.

Comparative effects of inorganic and three forms of organic trace minerals on growth performance, carcass traits, immunity, and profitability of broilers.

OBJECTIVE: The experiment was conducted to investigate the comparative effects of inorganic trace minerals (ITM) and three forms of organic trace minerals (OTM) (propionate, metho-chelated, and proteinate) on growth performance, edible meat yield, immunity, and profitability of commercial broilers. MATERIALS AND METHODS: A corn-soya based mash diet comprising four treatments each of 10 replicates were fed to 720 day-old Cobb 500 broiler chicks for 35 days (starter diet 0-21 days and grower diet 22-35 days). The diets for comparison were as follows: diet 1: control diet with ITM premix at 1 kg/ton of feed (T1); diet 2: control diet supplemented with propionate trace minerals at 600 gm/ton (T2); diet 3: control diet supplemented with metho-chelated trace minerals at 500 gm/ton by reducing 225 gm methionine/ton of feed (T3); and diet 4: control diet supplemented with proteinate trace minerals at 500 gm/ton of feed (T4). Growth performance, carcass yield, and antibody titer (AT) data were recorded. Data were analyzed and interpreted using SAS Computer Package Program version 9.1. RESULTS: Feeding propionate and proteinate OTM showed similar performance. Birds fed these two types (propionate and proteinate) or OTM had better performance in comparison with those receiving ITM and metho-chelated one. Proteinate group produced more wing meat and propionate group showed higher breast and drumstick meat yield as compared with those received the metho-chelated trace mineral and ITM. The birds belonging to OTM groups showed significantly higher AT level against infectious bursal disease. Proteinate minerals groups showed higher profitability followed by propionate fed broilers. CONCLUSION: Two forms of OTM, propionate and proteinate improved performance of commercial broilers over those of ITM and metho-chelated one.

Bitter Taste Sensitivity and the Expression of Bitter Taste Receptors at Different Growth Stages of Chicks.

Bitterness is one of the five basic tastes, and sensitivity to bitterness is important in that it enables animals to avoid harmful and toxic substances. In humans, taste sensitivity decreases with age, although the extent of loss varies depending on the taste quality. In chickens (Gallus gallus domesticus), baby chicks have been found to be more sensitive to salt and sour taste qualities than adults. In this study, therefore, we investigated the growth-associated changes in bitter taste sensitivity in chicks. We examined the behavioral perceptions toward the bitter compounds chloramphenicol and andrographolide in chicks at three different growth stages. Then, we measured the relative expression of the functional bitter taste receptors in the chick palate. In behavioral drinking tests, the 0-1-week-old chicks consumed a significantly lower amount of bitter solutions than water, whereas the 8-9-week-old chicks showed lower avoidance of the bitter solutions than the 0-1-week-old and 4-5-week-old chicks. Real-time PCR assay showed that the 0-1-week-old chicks had significantly higher expression of one of the functional bitter taste receptors in the palate than that in the older chicks. These results suggest that baby chicks are more sensitive to bitterness than older chicks. These findings may be useful in the production of new feedstuff for chicks according to their growth stages.

Identification of functional bitter taste receptors and their antagonist in chickens.

Elucidation of the taste sense of chickens is important not only for the development of chicken feedstuffs for the chicken industry but also to help clarify the evolution of the taste sense among animals. There are three putative chicken bitter taste receptors, chicken T2R1 (cT2R1), cT2R2 and cT2R7, which were identified using genome information and cell-based assays. Previously, we have shown that cT2R1 is a functional bitter taste receptor through both cell-based assays and behavioral tests. In this study, therefore, we focused on the sensitivities of the other two bitter receptors, cT2R2 and cT2R7, by using their agonists in behavioral tests. We tested three agonists of cT2R2 and three agonists of cT2R7. In a 10-min drinking study, the intakes of cT2R2 agonist solutions were not different from that of water. On the other hand, the intakes of cT2R7 agonist solutions were significantly lower compared to water. In addition, we constructed cT2R1-and cT2R7-expressing cells in order to search for an antagonist for these functional bitter taste receptors. By using Ca2+ imaging methods, we found that 6-methoxyflavanone (6-meth) can inhibit the activities of both cT2R1 and cT2R7. Moreover, 6-meth also inhibited the reduction of the intake of bitter solutions containing cT2R1 or cT2R7 agonists in behavioral tests. Taken together, these results suggested that cT2R7 is a functional bitter taste receptor like cT2R1, but that cT2R2 is not, and that 6-meth is an antagonist for these two functional chicken bitter taste receptors. This is the first identification of an antagonist of chicken bitter receptors.