THE MODULATING EFFECT OF TAURINE ON CIRCADIAN RHYTHM OF SERUM CALCIUM IN MALE BROILER CHICKENS DURING HOT-DRY SEASON.

Résumé

An experiment was conducted to study the modulatory effect of supplemental taurine on rhythm of serum calcium in male broiler chickens of different ages during the hot-dry season. Twenty, 21-day old Arbor Acre male broiler chickens were assigned ten each to control (Cgp) and treatment (Tgp) groups in a completely randomized design. The broiler chickens in the Tgp were served drinking water which contained taurine at a dose rate of 0.1% and the Cgp, clean drinking water ad libitum along with their standard diet from day 21 to 42 of the study period. Two (2mL) millilitres of blood samples was collected from the wing vein from each broiler chicken in the respective groups on a four-hourly basis over a 24 h period on scheduled days 28, 35 and 42. Serum samples were harvested for determination of serum calcium concentration using flame emission photometric method. The collected data was fitted into the single cosinor application, results showed serum calcium exhibited clear circadian rhythmicity in both groups. Taurine significantly (P < 0.05) increased the mesors of serum calcium in all age groups. The acrophases in Cgp fluctuated between the early (3.2 h) to the late (15.6 h) photophase, however, in Tgp the acrophases were restricted to the early photophase (7.9 h, 6.4 h and 7.4 h, respectively). It was concluded taurine modulated the rhythms of serum calcium in all age groups. The finding may be beneficial in combating low calcium ionization during heat stress, thereby improving calcium levels, regulating body temperature and improving immunity during the hot-dry season.