Effect of dietary protein content on live and carcase performance of heterozygous naked neck and normally feathered broilers

1. An experiment was conducted to determine the effect of different dietary protein contents on the performance of naked neck (Na/na) and normally feathered (na/na) broilers.

2. Chicks from the two genotypes were reared in wire‐floored cages and divided at random into 3 groups. Birds were fed on high protein (HP, 12.99 MJ ME, 238 g crude protein/kg and 12.94 MJ ME, 216 g crude protein/kg from 0 to 3 and 3 to 7 weeks, respectively), medium protein (MP, 12.99 MJ ME, 219 g crude protein/kg and 12.87 MJ ME, 201 g crude protein/kg from 0 to 3 and 3 to 7 weeks), and low protein (LP, 12.94 MJ ME, 205 g crude protein/kg and 12.75 MJ ME, 184 g protein/kg from 0 to 3 and 3 to 7 weeks) diets.

3. The LP diets resulted in a significantly lower daily body weight gain of males from 0 to 3 weeks. Dietary protein content had no effect on body weight gain from 3 to 7 weeks, body weight at 7 weeks, and the food intake of birds. Carcase composition of birds from both genotypes was unaffected by dietary protein.

4. Naked neck birds had significandy higher body weights at 7 weeks. Yields of carcase and breast of Na/na males were significantly higher than those of na/na males. There were no significant differences between females from the two genotypes as regards carcase yield.

5. It was concluded that the dietary protein requirements of naked neck birds were similar to those for normally feathered birds.     

The effects of agricultural fields and human settlements on the use of rivers by wildlife in the mid-Zambezi valley,Zimbabwe

After the eradication of the Tse-Tse fly in the Mid-Zambezi valley, human settlements and fields extended mainly along the main rivers. In order to investigate the consequences of this human development on wildlife diversity we monitored three rivers of the Mid-Zambezi valley in Zimbabwe: Angwa, Manyame and Kadzi. The rivers were divided in segments of 200 m which were checked for spoors in order to assess the number of species and the number of individuals that used the segments. Human settlements were also recorded. We used a GIS to define the spatial characteristics of the fields present along the rivers, and related them to the distribution and abundance of wild species spoors in the river beds and banks. Our results show that the number of species in one segment of the river decreased with the increasing size of the field area bordering the segment. For all the major ungulate species, the numbers of individuals recorded per segment decreased with increasing field area. A similar trend was observed for small and medium-sized carnivores, though they were in lower numbers when present. Our analyses thus confirm that the extension of human agriculture in wildlife areas has an impact on most wild species, but we also define some threshold value of field size above which there seem to be an acceleration of the decrease in wildlife density and diversity: 3.2 ha for medium and small herbivores and carnivores; only the elephant seem to tolerate larger field area with a threshold value of 32 ha.This revised version was published online in May 2005 with corrections to the Cover Date.     

Chromosomes of salmon (Salmo salar) by leukocyte culture

Chromosome preparations from salmon (Salmo salar) were obtained by means of leukocyte culture. The chromosome number varied from 55 to 60 with a clear maximum of 2n = 58. The chromosomes are tentatively grouped as follows: group A, two large submetacentrics; group B, 14 metacentrics; group C, two large telocentrics; group D, 22 medium telocentrics; group E, 18 small telocentrics.     

Harmonic radar: efficacy at detecting and recovering insects on agricultural host plants

BACKGROUND: In pest management research, harmonic radar systems have been largely used to study insect movement across open or vegetation‐poor areas because the microwave signal is attenuated by the high water content of vegetation. This study evaluated whether the efficacy of this technology is sufficient to track insects in vegetative landscapes. RESULTS: Field efficacy data were collected using portable harmonic microwave radar and electronic dipole tags mounted on adults of three economically important pests: Leptinotarsa decemlineata (Say), Diabrotica virginifera virginifera (LeComte) and Conotrachelus nenuphar Herbst. Detection and recovery of tagged Colorado potato beetles, plum curculios and western corn rootworms was high within and among potato plants, moderate within apple trees and high within, but not between, corn plants respectively. The efficacy of the radar depends on the ability of the operator to move around the host, scanning for a signal ‘sightline’ with the tagged insect among plant structures. CONCLUSION: The detection rate of tagged insects by harmonic radar systems is high enough to track the walking path of pests through low row crops such as potato, tall row crops such as corn or tall but well‐separated trees of orchard‐type crops by adapting the scanning procedure to the vegetative architecture. Copyright © 2010 Crown in the right of Canada. Published by JohnWiley & Sons, Ltd     

Littoral spawning habitats of three southern Arctic charr (Salvelinus alpinus L.) populations

Abstract Arctic charr populations in southern latitudes are nonmigratory, with all life‐stages limited to freshwater lakes and in‐ or out‐flowing tributaries. Although many of these populations are reported to also spawn in lake littorals, little is known about the physical characteristics of putative spawning grounds. A total of 23 discrete spawning sites within three Irish lakes were located by fyke netting of spawning adults and snorkelling in littoral habitats. Spawning sites were found to be long, narrow strips running parallel to the shore at a maximum depth of 124 cm. Spawning sites were limited to areas of coarse mineral substrate with an adequate (c. 8 cm) depth of clean interstitial spaces. In individual lakes, combined areas of spawning sites made up 0.4–0.7% of available littoral. Egg densities varied considerably between sites (33–900·eggs m^?2) and were significantly correlated with gradient and width of spawning sites. No evidence of redd digging was found. The shallow, localised and restricted nature of spawning grounds makes such populations vulnerable to anthropogenically induced postoviposition changes in surface water level, eutrophication processes such as increased lake sedimentation and elevated nutrient status.     

Production,chemical composition,and fatty acid profile of milk from buffaloes fed with cupuaçu (Theobroma grandiflorum) cake and murumuru (Astrocaryum murumuru) cake in the Eastern Amazon

The objective was to evaluate the effect of concentrate supplementation using by-products of the Amazonian industry on milk production, milk composition, and milk fatty acid profile of dairy buffaloes. Twelve lactating buffaloes (544.5 ± 35.6 kg, 6.4 ± 2.2 years old, 59 ± 6 days in milk) were allotted in a pasture of Mombaça grass and managed under rotational grazing (4 days occupancy/28 days rest). A 3 × 3 Latin square was adopted, and each animal alternately received three supplementary treatments based on corn bran + soybean meal or cupuaçu cake or murumuru cake for 21 days per treatment. Murumuru cake increased the levels of lauric acid and myristic acid in the milk (p < 0.05). Murumuru cake reduced the unsaturated fatty acid contents in the milk compared with animals fed control diet or cupuaçu cake (24.27% vs. 25.24% vs. 25.08%). The n-6/n-3 ratio was 2.6, 1.97, and 2.0 in the control, cupuaçu, and murumuru groups, respectively. Based on this parameter, cakes made from cupuaçu as well as murumuru could be considered to be adequate for inclusion in dairy water buffalo feed. However, the murumuru cake addition requires some caution because its use induces the secretion of higher levels of lauric and myristic fatty acids that are related to human cardiovascular disease.     

Canine fetal echocardiography: correlations for the analysis of cardiac dimensions

The aim of this study was to develop regression models for correlation of canine fetal heart development with body size to characterize normal development or suggest cardiac anomalies. Twenty clinically healthy pregnant bitches, either brachycephalic and non-brachycephalic, were examined ultrasonographically. Transabdominal fetal echocardiography was conducted every 4 days from the beginning of cardiac chambers differentiation until parturition. Ten cardiac parameters were measured: length, width and diameter of the heart; heart area; left and right ventricular dimensions; left and right atrial dimensions; and aortic and pulmonary artery diameter. Femoral length, biparietal diameter and abdominal cross-sectional area were also recorded. Regression equations were developed for each parameter of fetal body size, and linear and logarithmic models were compared. The model with the highest correlation coefficient was chosen to produce equations to calculate relative dimensions based on the correlations. Only the left-ventricular chamber differed between the two racial groups. Biparietal diameter was the independent parameter that produced the highest correlation coefficient for the most fetal cardiac dimensions, although good correlations were also observed using femoral length and abdominal cross-sectional area. Heart width and heart diameter were used as surrogates of cardiac development, as these measurements showed the best statistical correlation. Quantitative evaluation of fetal cardiac structures can be used to monitor normal and abnormal cardiac development.     

Strategy to identify resistance to white mould associated with high yield for irrigated common bean in Brazil

Development of common bean cultivars with partial white mould resistance through breeding techniques has been a challenge in Brazil. As yet, lines/cultivars from breeding programmes have not been investigated for resistance; therefore, this study screened 107 lines/cultivars for their reactions to white mould in 14 preliminary trials conducted under irrigation. Thirteen resistant lines/cultivars (three of Andean origin) and six Mesoamerican cultivars (three intermediately resistant and three susceptible) were selected for further investigation. These lines/cultivars and the resistant control A195 were evaluated in six advanced trials and two straw tests to assess the effectiveness of the screening procedure. In 11 preliminary trials, screenings were performed under moderate/high or higher disease pressure. These pressures occurred in two advanced trials in which, when yields were averaged across moderate/high and high pressures, 10 Mesoamerican lines/cultivars selected for resistance yielded 14%, 23%, and 38% more than intermediately resistant cultivars, A195, and susceptible cultivars, with median disease ratings (1–9 scale) of 4.5, 5.7, 5.7, and 6.7, respectively. In the straw test, three Andean lines/cultivars (A195 included) and two susceptible cultivars in the field were among those with the highest levels of physiological resistance. Thus, field rating under high disease pressure and greenhouse rating did not correlate significantly, suggesting that field trials are critical to evaluating resistance and to identifying high-yielding beans. Therefore, lines/cultivars from breeding programmes assessed in field trials may provide a low cost and fast way to identify high-yielding bean cultivars with partial resistance to white mould in the subtropical southern hemisphere.