Are dual-purpose and male layer chickens more resilient against a low-protein-low-soybean diet than slow-growing broilers?

ABSTRACT

1. Although fattening dual-purpose types or male layer hybrid chickens appears more ethical than the common practice of culling day-old male layer chicks, the lower feed efficiency of these birds raises concerns. Replacing feed ingredients that compete with food production by those of lower value for human nutrition would be beneficial.

2. Lohmann Dual (LD), a modern dual-purpose type, Lohmann Brown (LB), a male layer hybrid, and Hubbard JA 957 (HU), a slow-growing broiler type, were fattened for nine weeks on two diets (control or ?20% crude protein; n = 6 × 12 birds). Growth, carcass and meat quality were analysed.

3. Growth performance of HU exceeded that of LD and especially of LB. The growth depression caused by the low-protein diet fed to LD (?7%) was only half of that found in HU (?13%). The LD fed the control diet had the same feed efficiency as the HU fed the low-protein diet. Even the LB had a lower performance and feed efficiency with the low-protein diet in growth. There was a gradient in carcass properties (weight, dressing percentage, breast meat yield, breast proportion and breast angle) from HU to LD to LB, with some additional adverse effects of the low-protein diet especially in HU. There were some breed differences in fatty acid profile in the intramuscular fat.

4. In conclusion, the dual-purpose type used complied with regulations for Swiss organic poultry systems in terms of growth rate and was found to respond less when fed a low-protein diet than the slow-growing broiler type. The LB males were inferior in all growth and carcass quality traits. Future studies need to determine the exact protein and amino acid requirements of dual-purpose and layer hybrid chickens and the economic feasibility of the systems, especially for organic farming.     

Air pollution: sensitive detection of ten pollutant gases by carbon monoxide and carbon dioxide lasers

Detection sensitivities of a few parts per billion for ten gaseous pollutants have been evaluated by measuring the strength of the absorption of infrared radiation from carbon monoxide and carbon dioxide lasers. Ethylene concentrations as small as 5 parts per billion have been detected in air. The measured absorption strengths indicate that in mixtures of pollutants, such as nitrogen dioxide and water vapor, the sensitivity is reduced by overlapping absorption bands. However, calculations indicate that it should be possible to detect nitrogen dioxide concentrations of 0.01 part per million in the presence of water vapor concentrations of 105 parts per million.     

Intensity of browsing on trees and shrubs under experimental variation of cattle stocking densities in southern Bolivia

Mountain forests are traditionally used for cattle grazing during the dry season in southern Bolivia. To evaluate browsing intensity and damage to young trees and shrubs, a forest grazing area was monitored for about 3 months in both 2006 and 2007. Three similar paddocks of about 3 ha each, consisting of grassland and forest in a ratio of about 1:3 were stocked with 0.9, 1.6 and 2.6 tropical livestock units per ha (equivalents of 250 kg of body weight), reflecting low, medium and high stocking densities. Six 5 m × 5 m plots were mapped out within each paddock in 2006. Three additional plots per paddock were added in 2007. Within plots, the individuals of 18 woody species were coded and evaluated weekly for intensity of browsing. Intensity was quantified using five-scale categories reflecting the proportions of plant tissue removed (0 = no browsing, 1 = 1–25%, 2 = 26–50%, 3 = 51–75% and 4 = 76–100%). Across all plant species, the average category of browsing intensity, as determined in the post-grazing evaluation, was affected (P < 0.001) by stocking density. Browsing intensity increased in an approximately linear manner from 1.58 to 2.18 and 2.77 with low, medium and high stocking density, respectively. There was no significant difference between years. Most woody species followed the same general response pattern to stocking density, although some species were only noticeably browsed at high stocking density while a few others were intensively browsed at all stocking densities. The onset of browsing on woody species was observed only after some weeks had passed, indicating that herbaceous plants were preferred as a forage resource. The proportion of fatally damaged individuals, as assessed about 8 months after grazing in 2006, were 10.6%, 8.6% and 11.4% for low, medium and high stocking density, respectively. The percentage of completely browsed individuals increased with stocking density, but 80% of those plant individuals recovered following a resting period of 8 months. However, although most woody species recovered from browsing and fatal damage was infrequent, long-term changes in woody plant species composition and structure caused by grazing cannot be excluded. High stocking density in particular may reduce the vigour of heavily browsed species.     

Grazing of a common species of soil protozoa (Acanthamoeba castellanii) affects rhizosphere bacterial community composition and root architecture of rice (Oryza sativa L.)

We performed a controlled experiment with rice seedlings (Oryza sativa L.) growing in Petri dishes on homogeneous nutrient agar containing a simple rhizosphere food web consisting of a diverse bacterial community and a common soil protozoa, Acanthamoeba castellanii, as bacterial grazer. Presence of amoebae increased bacterial activity and significantly changed the community composition and spatial distribution of bacteria in the rhizosphere. In particular, Betaproteobacteria did benefit from protozoan grazing. We hypothesize that the changes in bacterial community composition affected the root architecture of rice plants. These effects on root architecture affect a fundamental aspect of plant productivity. Root systems in presence of protozoa were characterized by high numbers of elongated (L-type) laterals, those laterals that are a prerequisite for the construction of branched root systems. This was in sharp contrast to root system development in absence of protozoa, where high numbers of lateral root primordia and short (S-type) laterals occurred which did not grow out of the rhizosphere region of the axile root. As a consequence of nutrient release from grazed bacteria and changes in root architecture, the nitrogen content of rice shoots increased by 45% in presence of protozoa. Our study illustrates that interactions over three trophic levels, i.e. between plants, bacteria and protozoa significantly modify root architecture and nutrient uptake by plants.     

Characterisation of the acute phase response of heifers to a prolonged low dose infusion of lipopolysaccharide

The effect of a prolonged low dose infusion of bacterial lipopolysaccharide (LPs) on acute phase-like reactions was examined in heifers. LPS (2 μg kg⁻¹ dissolved in 100 ml water), or saline was infused (at 1 ml min⁻¹) intravenously for 100 minutes and blood samples were taken at various times before, during and after the infusion. The serum concentrations of tumour necrosis factor-alpha(TNFα), interleukin-Ibeta (IL-1β), interleukin-6 (IL-6) and serum amyloid A (SAA) and the rectal temperature increased in response to the LPS infusion. Serum TNFα increased before the increases in IL-1β and IL-6 and remained high from 20 minutes after the onset of the infusion until the end of the sampling period (six hours). The LPS-induced increases in serum IL-1β and IL-6 were biphasic. Plasma cortisol and lactate concentrations also increased, and plasma glucose and B-hydroxybutyrate concentrations decreased in response to the LPS infusion. The similarity of these reactions to changes observed in response to bacterial infections shows that the prolonged infusion of low doses of LPS is a good model for studying the acute phase response to Gramnegative bacterial infection in heifers.     

Stable carbon isotope composition of perirenal adipose tissue fatty acids from Engadine sheep grazing either mountain or lowland pasture

To provide further insights into ruminant lipid digestion and metabolism, and into cis-9,trans-11 18:2 synthesis, 12 growing Engadine lambs grazing either mountain pasture (2,250 m above sea level; n = 6) or lowland pasture (400 m above sea level; n = 6) were studied. Both pastures consisted exclusively of C(3) plants. Before the experiment, all animals grazed a common pasture for 6 wk. Grasses and perirenal adipose tissues of the sheep were analyzed for fatty acids by gas chromatography. Stable C-isotope ratios (δ(13)C values in ‰ vs. the Vienna Pee Dee Belemnite standard) were determined in the composite samples by elemental analysis-isotope ratio mass spectrometry. The δ(13)C of the individual fatty acids were measured by gas chromatography-combustion-isotope ratio mass spectrometry. The δ(13)C value of the entire mountain pasture grass was -27.5‰ (SD 0.31), whereas that of the lowland pasture grass was -30.0‰ (SD 0.07). This difference was reflected in the perirenal adipose tissues of the corresponding sheep (P < 0.05), even though the δ(13)C values were less in the animals than in the grass. The δ(13)C values for cis-9 16:1 and cis-9 18:1 in perirenal fat differed between mountain and lowland lambs (P < 0.05). The 16:0 in the adipose tissue was enriched in (13)C by 5‰ compared with the dietary 16:0, likely as a result of partly endogenous synthesis. The δ(13)C values of cis-9,trans-11 18:2 (cis-9,trans-11 CLA) in the adipose tissue were smaller than those of its dietary precursors, cis-9,cis-12 18:2 and cis-9,cis-12,cis-15 18:3; conversely, the δ(13)C values of trans-11 18:1 were not, suggesting that large proportions of perirenal cis-9,trans-11 18:2 were of endogenous origin and discrimination against (13)C occurred during Δ(9)-desaturation. The same discrimination was indicated by the isotopic shift between 16:0 and cis-9 16:1 in the mountain grazing group. Furthermore, the δ(13)C values of cis-9,trans-11 18:2 were smaller relative to the precursor fatty acids in the mountain lambs compared with the lowland group. This result suggests a reduced extent of biohydrogenation in lambs grazing on mountain grass in comparison with those grazing on lowland grass. This was supported by the smaller cis-9,trans-11 18:2 concentrations in total fatty acids found in the adipose tissues of the lowland lambs (P < 0.001). The results of this study demonstrate that natural differences between δ(13)C values of swards from different pastures and the adipose tissue fatty acids could be used as tracers in studies of lipid metabolism in ruminants.     

Methods of staining and visualization of sphingolipid enriched and non-enriched plasma membrane regions of Arabidopsis thaliana with fluorescent dyes and lipid analogues

ABSTRACT: BACKGROUND: Sterols and Sphingolipids form lipid clusters in the plasma membranes of cell types throughout the animal and plant kingdoms. These lipid domains provide a medium for protein signaling complexes at the plasma membrane and are also observed to be principal regions of membrane contact at the inception of infection. We visualized different specific fluorescent lipophilic stains of the both sphingolipid enriched and non-sphingolipid enriched regions in the plasma membranes of live protoplasts of Arabidopsis thaliana. RESULTS: Lipid staining protocols for several fluorescent lipid analogues in plants are presented. The most emphasis was placed on successful protocols for the single and dual staining of sphingolipid enriched regions and exclusion of sphingolipid enriched regions on the plasma membrane of Arabidopsis thaliana protoplasts. A secondary focus was placed to ensure that these staining protocols presented still maintain cell viability. Furthermore, the protocols were successfully tested with the spectrally sensitive dye Laurdan. CONCLUSION: Almost all existing staining procedures of the plasma membrane with fluorescent lipid analogues are specified for animal cells and tissues. In order to develop lipid staining protocols for plants, procedures were established with critical steps for the plasma membrane staining of Arabidopsis leaf tissue and protoplasts. The success of the plasma membrane staining protocols was additionally verified by measurements of lipid dynamics by the fluorescence recovery after photobleaching technique and by the observation of new phenomena such as time dependent lipid polarization events in living protoplasts, for which a putative physiological relevance is suggested.