I report an unexpected negative covariance occurring between two major parameters governing shell growth in marine bivalves, especially within the order Veneroida. This relationship is highlighted, here, considering a set of forty, rather common species of clams collected from French coasts. Interestingly, this negative covariance has two (geometrically related) consequences on the pattern of variation of shell shape at the inter-specific level:
(i) An extended range of variation of shell elongation ‘E’ is made compatible with.
(ii) A severely restricted range of variation of the ventral convexity ‘K’ of the shell contour.
I suggest that:
(i) The extended range of interspecific variation of the shell elongation ‘E’ results from a trend towards larger differentiation between species according to this functionally important parameter E, while, in contrast,
(ii) The strongly restricted range of variation of the ventral convexity ‘K’ of the shell contour might arguably result from a common need for improved shell resistance, face to mechanical solicitations from the environment, either biotic or abiotic.
Accordingly, the negative covariance reported between these two growth parameters is understood as the indirect consequence of the selective pressures applying primarily upon the functionally-relevant shell shape parameters E and K.
Aims: To evaluate the utilization of cowpea testa meal supplemented with or without enzyme maxigrain® on broiler chicken growth performance.
Study Design: Completely randomized design.
Place and Duration of Study: The study was conducted at a Commercial Poultry Farm in Yola, Nigeria between the months of October and December 2016.
Methodology: Experimental diets were compounded using Cowpea testa meal (CTM). The CTM replaced wheat offal at 0, 25, 50, 70 and 100%. 0.20 g/kg enzyme maxigrain® was supplemented at two levels (with and without). Four hundred (400) unsexed day old Anak 2000 were used, the birds were brooded for two weeks on commercial starter diet and then randomly assigned to dietary treatments of four replicates with ten birds per replicate in a 5 x 2 factorial arrangement in a completely randomized design. Each replicate was housed in 3 × 3m deep litter pens fitted with wood shavings, feeders and drinkers.
Results: Birds fed replacement levels of CTM without enzyme supplementation showed significantly decrease (P<0.05) in average final body weight and daily weight gain as the levels of replacement in the diets, while average daily feed intake, feed conversion ratio, feed cost and feed cost per kg weight gain increased. Enzyme supplemented CTM showed significant (P<0.05) improvement in average daily weight gain, final body weight gain and a decrease in feed intake, feed cost and feed cost per kg weight gain over non-supplemented birds.
Conclusion: It was concluded that CTM can replace wheat offal 100% with 0.20g/kg Maxagrain® in broiler chicken diets.
This study investigated effects of baobab pulp (Adansonia digitata), Amaranthus hybridus and tiger nut (Cyperus esculenthus) on growth performance, cost-benefit indices and nutrient retention of heat-stressed broilers. The test ingredients were crude sources of vitamins A, C and E functioning as anti-stress for broilers during a hot-dry season. A total of 240 unsexed broiler chicks were used for the study in a completely randomized design (CRD), which lasted for 8 weeks. The birds were allotted to six treatments (each contained 40 chicks) of four replicates each. Test ingredients were included in the starter and finisher diets at 1%. Diet 1 (T1) served as the control. T2, T3, T4 and T5 contained synthetic vitamin C, baobab pulp, amaranthus and tiger nut seed respectively. T6 contained 0.3% each of baobab, amaranthus and tiger nut. Results from the study revealed that there were significant (P<0.05) differences in the performance indices and the nutrient retained by the birds. Broiler chickens fed baobab pulp (crude source of vitamin C, T3) had significantly more profit (P<0.05), better final body weight (P<0.05) and crude protein retention (P<0.05) than those fed amaranthus (T4), tiger nut (T5) and the mixture of the test ingredients (T6). Feed conversion ratio was at the best (1.58) in T3 while T5 gave the worst (1.64) at 4th week. Birds fed T1 gave the best (1.07) feed conversion ratio while T4 had the worst (1.26) at 8th week. T2, T3 and T5 had the least (10%) mortality compared with those fed control diet (T1), amaranthus (T4) and the mixture (T6). In conclusion, the study showed that baobab pulp could replace synthetic vitamin C as antioxidant based on growth performance of broilers and its accrued profitability during a hot-dry season in the tropics.
A cross sectional study was carried out in local poultry abattoirs at Monday and Gamboru markets Maiduguri, Nigeria to determine the occurrence of Staphylococcus aureus in rural chickens, slaughter environment and personnel. A total of 600 samples were collected and analyzed using standard bacteriological techniques. The samples were taken from featherless skin under the wings of the rural chickens, the dressing tables, containers, knives and from skin and nostrils of slaughter personnel. A sum of 135 (22.5%) S. aureus were isolated with significantly higher proportion from the utensils 75 (55.5%), 53 (39.3%)from skin of rural chickens while 3(2.2%) and 4(3.0%) were obtained from the skin and nostrils of the personnel respectively.The antibiotic susceptibility pattern of the S. aureus isolates was tested against eight (8) antibiotics where high resistance was observed against tetracycline (68.1%), erythromycin (60.7%) and sulphamethoxazole (52%), while high susceptibility was observed in ciprofloxacin (100%), cephazolin (93.3%), gentamicin (86.7%) and chloramphenicol (77.8%). These results indicated a high frequency of isolation of S. aureus from processing utensils and could possibly be exchanged between rural chickens and personnel, either directly or through the contaminated environment. There is, therefore, the need for strict hygiene practices on the side of the personnel to minimize chances of cross contamination either from the rural chicken to the personnel or to the environment and vice vasa. There is also the need for creating awareness amongst the slaughter personnel on the potential occupational hazards associated with unhygienic practices.
An experiment was conducted to determine the response of broiler chickens under dexamethasone induced stress conditions. The experiment was conducted using two hundred and forty days old Arbor acre broiler chickens. There were four treatments each having three replicates with twenty birds per replicate. Concentrations of dexamethasone at 0, 1, 2 and 3 mg/ L of water were supplied daily. The experiment lasted 56 days. A decrease (P>0.05) in rectal temperature with an increase (P>0.05) in respiratory rate with increasing dose of dexamethasone was observed. Birds receiving 0 mg dexamethasone had the highest (P<0.05) final body weight, average daily weight gain, average daily feed intake and feed conversion ratio. Dexamethasone effect on tibia weight, length, weight/length index and robusticity index was significant (P<0.05) with the control group performing better than the dexamethasone groups. It is concluded that dexamethasone-induced stress had negative effects on broilers performance and tibia geometric properties.