Thermotolerance Traits and Mortality Levels of Three Strains of Broilers in Humid Tropics (Published)
The tolerance of three temperate breeds of broilers to tropical heat condition was evaluated at the poultry unit of Department of Animal and Environmental Biology, Adekunle Ajasin University, Akungba-Akoko, Nigeria. One hundred and fifty (150) day-old broiler chicks comprising of Arbo acre, Cobb and Marshall breeds were raised under the same management condition for 8 weeks.Thermotolerance traits were measured and mortality of the broilers were recorded. Analysis of variance showed that Cobb broiler strain had the least cloacal temperature (40.89±0.03oC) followed by Arbo acre (41.06±0.05oC) while Marshall Broiler strain had the highest cloacal temperature (41.55 ± 0.06oC). Cobb strain also had the lowest respiratory rate (51.16 ± 0.15 breath/min).The respiratory rate of Marshall strain (56.80± 0.45 breath/min) was significantly higher than that of Arbo acre strain (54.63 ± 0.24 breath/min) . Marshall Strain had the highest pulse rate (73.50 ± 0.70 beats/min) while the least pulse rate (66.40 ± 0.47 beats/min) was found in Cobb breed. The least heat stress index was recorded for Cobb breed. The effect of strain was also significant on the mortality levels of the broilers. Marshall Strain had the highest total mortality percentage followed by Arbo acre while the least total mortality percentage was recorded for Cobb breed. The effect of age was significant on all the parameters studied (p<0.05).Young broilers were less tolerant to heat stress than older broilers. Mortality percentage also reduces with advance in age. The effect of sex was also significant on the thermotolerance traits. Females’ broilers were less tolerant to thermal stress. In conclusion, there was genetic variation in the thermotolerance traits of broilers. Cobb strain tolerated heat stress better than Arbo acre and Marshall Strain in the humid tropics.
Dietary effect of substituting mixed saw dust for wheat offal on internal organ and linear body measurement of broiler finisher (Published)
Dietary effect of substituting mixed saw dust for wheat offal on internal organ and linear body measurement of broiler finisher was conducted using ninety (90) broilers. The broilers were allocated to three dietary treatments consisting of three (3) replicates of ten (10) birds in each replicate. Three dietary treatments were formulated with the mixed saw dust substituting wheat offal at 0%, 35 and 70% level of inclusion respectively. The experiment lasted for four (4) weeks. The experiment was arranged in a Completely Randomized Design (CRD). Data obtained was analyzed using ANOVA. At the end of the experiment, result showed that there were significant (p< 0.05) difference in the values recorded for the internal organ of broiler across the treatment. The highest liver weight (1.62%) was recorded for birds fed control diet, while the lowest liver weight (1.50%) was recorded for birds on T3. Birds on T1 and T2 had a liver value which is statistically similar and differs from birds on T3. The lowest value (0.40%) recorded for heart was observed in broiler fed with (35%) T2, while the highest heart value (0.50%) was recorded for broiler fed diet 3. The highest kidney weight (0.50%) was recorded for birds on control diet, while the lowest kidney weight (0.32%) was recorded for birds diet 2. Birds on diet 2 had the highest spleen weight, while the lowest spleen weight (0.00%) was recorded for birds on control diet. For linear body weight however, It was observed that the values recorded for all linear body parameters were significantly (P<0.05) differences across the dietary treatments, with the exception of body length, shank length and girth length which showed no significant differences across the dietary treatments. The highest value (2591.00g) of final live weight was noticed in birds fed control diet, while the lowest value (2394.00g) of final live weight was recorded for birds on treatment 3. There were significant (P<0.05) different in the value obtain for average weight gain across the dietary treatment. The value obtained fluctuates as the substitution level of mixed sawdust for wheat offal increased. The highest value (1313.00g) of weight gain was recorded for birds on control, while the lowest value (1119.00g) was obtained in birds on diet 2.It can be concluded that mixed saw dust can be given to birds without having any negative effects on the organ weight and the linear body measurement of broiler birds
Performance Response and Carcass Characteristics of Broilers Fed Dietary Antibiotics, Probiotics and Prebiotics (Published)
An experiment was conducted for six weeks to investigate the effect of antibiotics, probiotics and prebiotics as feed additives in broiler diets to check for their effects on performance and carcass characteristics. A total of 250 unsexed Abor-acre broiler chicks were randomly allotted into 5 treatment groups containing 5 replicates with 10 birds per replicate. All birds were subjected to the same environmental conditions. The treatments were assigned into 5 dietary treatments containing 0.01% antibiotics, 0.06% probiotics, 0.1% probiotics and 0.2% prebiotics while the first treatment which served as the control did not include anything. Parameters on performance (feed intake, weight gain, feed conversion ratio and the feed efficiency ratio) and carcass characteristics (live and dressed weight, head, neck, breast, back, wings, drumsticks, thigh, shank, gizzard, lungs, liver, spleen, heart and bursa of fabricius) was evaluated. Data were subjected to analysis of variance (ANOVA) procedure of SAS, 2010. It was observed that birds fed with probiotics had the highest weight gain (1218.15g and 1163.68g) and high feed intake, relatively high weight in wings when compared with other treatments. The inclusion of probiotics at certain level increases growth performance, relatively high value in some parts of carcass and the values are closer to those fed antibiotics. It thus shows that probiotics can be used to replace antibiotics.