Effect of neutral detergent soluble fibre on digestion, intestinal microbiota and performance in twenty five day old weaned rabbits

The effect of neutral detergent soluble fibre (NDSF) level on digestibility, fermentation traits, intestinal microbiota and performance was studied in weaned rabbits. A control diet (DA) containing 103 g NDSF/kg DM included dehydrated alfalfa as the main source of fibre. Another diet (B-AP) was formulated by replacing half of the dehydrated alfalfa with a mixture of beet and apple pulp resulting in 131 g NDSF/kg DM. A third diet (OH) was obtained by substituting half of the dehydrated alfalfa with a mix of oat hulls and a soybean protein concentrate and contained 79 g NDSF/kg DM. All diets contained similar levels of total fibre (NDSF + neutral detergent fibre), starch and protein (446, 208, and 199 g/kg DM, respectively). Forty-two rabbits (14/diet) weaned at 25 days were used to determine faecal digestibility from 32 to 35 days of age. This group, plus another nine rabbits/diet (23/diet), were used to determine weight of stomach and caecum and their contents, caecal fermentation traits and similarity rate (SR) of intestinal microbiota. Another 105 and 245 weaned rabbits were used to determine growth traits and mortality, respectively. From 25 to 39 days of age, rabbits were fed the experimental diets and from 39 to 60 days they were fed a commercial diet, including robenidine hydrochloride in all diets. Drinking water was supplemented with apramicine sulfate and tylosine tartrate throughout the experimental period. Faecal and energy digestibility increased linearly by 8% and NDF digestibility by 43% between extreme diets with NDSF inclusion (P < 0.001). Weight of total gastrointestinal tract decreased linearly and quadratically with NDSF reduction (P = 0.008 and P = 0.089, respectively). Stomach pH decreased linearly with increasing levels of NDSF (P ≤ 0.041). Weight of caecal contents increased linearly between animals fed OH and B-AP diets (P < 0.001). Level of inclusion of NDSF had no effect (P ≥ 0.12) on pH, VFA concentration and VFA molar proportions in caecal contents. Treatments appeared to influence the SR of caecal microbiota but a lesser effect was observed on ileal microbiota. Post weaning feed efficiency (25–39 days) increased linearly (P < 0.001) with NDSF inclusion by 10% between extreme diets, and by 3% in the whole fattening period (P = 0.027). Average feed intake during the post weaning (25–39 days) and the whole fattening period increased with NDSF reduction (P ≤ 0.079). No effect of NDSF was detected on average daily gain (P ≥ 0.15). Mortality decreased linearly with increasing levels of NDSF in the post weaning and in the whole fattening period (P = 0.086 and 0.016, respectively).     

Selecting earlywood vessels to maximize their environmental signal

The anatomical features of earlywood vessels often reflect information about past climatic conditions. We examined the relationships between mean monthly temperature and mean vessel lumen area (MVA) in various categories of earlywood vessels. Subsets of earlywood vessels of chestnut (Castanea sativa Mill.) were selected from a previously reported dataset based on several progressive size-related procedures. To include all earlywood vessels, the minimum size considered was 10,000 microm2. Changes in the correlations between MVA and the mean air temperature in March are described and discussed. The results show that not all vessels embody the same information. The MVA of a proportion of the largest earlywood vessels in each annual ring was most closely related to March temperature, whereas MVA of the smallest earlywood vessels was better correlated with June temperature. This difference is probably a result of the vessels being formed at different times: early spring for the largest earlywood vessels and later in spring for the smallest earlywood vessels. Analyses combining large and small vessels yielded lower correlations between MVA and monthly temperature. The number, size and distribution of vessels can vary greatly from ring to ring. In making year-to-year comparisons, the best information is provided by observations on vessels of contemporaneous ontogenesis. Criteria for the selection and analysis of vessels in the assessment of temperature during the season of wood formation are proposed and discussed.     

Postanesthetic brachial triceps myonecrosis in a Spanish-bred horse

This report describes a case of postanesthetic brachial triceps myonecrosis affecting only the left forelimb of a horse. A fatal unilateral postanesthetic myonecrosis has not been previously reported in the horse. This article describes the factors in the horse’s history, the anesthetic protocol, and the treatment that may have led to this condition.     

Evaluation of four commercial serum ELISAs for detection of Mycobacterium avium subsp. paratuberculosis infection in dairy cows

During the first 3 months of 2006, a study was performed on four dairy cattle herds with a history of clinical paratuberculosis, to evaluate different enzyme-linked immunosorbent assays (ELISAs). Serum samples obtained from 326 animals were analysed using four ELISAs to detect antibodies to Mycobacterium avium subsp. paratuberculosis (MAP). Kappa (kappa) concordance coefficients in pairwise comparisons of the ELISA outcomes ranged up to 0.22 (linear kappa) and 0.25 (quadratic kappa). When the borderline positives obtained were considered as negatives, kappa values remained low (kappa up to 0.19). Having performed the serological tests, faecal samples were then obtained from 55 animals (including all animals testing positive in two or more ELISAs) from the same herds. Faecal culture and faecal polymerase chain reaction (PCR) for the detection of MAP were negative in all cases. The results indicate that neither the currently available serum ELISAs nor faecal culture and PCR are effective for the early detection of MAP in dairy cattle.     

Mixed models including environmental covariables for studying QTL by environment interaction

The study of the phenotypic responses of a set of genotypes in their dependence on the environment has always been an important area of research in plant breeding. Non-parallelism of those responses is called genotype by environment interaction (GEI). GEI especially affects plant breeding strategies, when the phenotypic superiority of genotypes changes in relation to the environment. The study of the genetic basis of GEI involves the modelling of quantitative trait locus (QTL) expression in its dependence on environmental factors. We present a modelling framework for studying the interaction between QTL and environment, using regression models in a mixed model context. We integrate regression models for QTL main effect expression with factorial regression models for genotype by environment interaction, and, in addition, take care to model adequately the residual genetic variation. Factorial regression models describe GEI as differential genotypic sensitivity to one or more environmental covariables. We show how factorial regression models can be generalized to make also QTL expression dependent on environmental covariables. As an illustrative example, we reanalyzed yield data from the North American Barley Genome Project. QTL by environment interaction for yield, as identified at the 2H chromosome could be described as QTL expression in relation to the magnitude of the temperature range during heading. This revised version was published online in July 2006 with corrections to the Cover Date.     

Analysis of natural allelic variation in in vitro organogenesis of Arabidopsis thaliana

We have evaluated the regeneration ability of leaf and root explants in 26 natural populations with the aim of analyzing the naturally occurring variation of Arabidopsis in vitro shoot and root organogenesis. All the accessions have been used as parental lines of available or under construction recombinant inbred lines (RILs) under construction. Phenotypic differences found between Ler and Cvi ecotypes were mapped in a population of 162 RILs. Several involved quantitative trait loci (QTL) have been identified. The analysis of near isogenic lines (NILs) would allow us to assign the effect of the QTLs identified and also possible candidate genes will be tested among those already described in the literature mapping into those regions. This revised version was published online in July 2006 with corrections to the Cover Date.     

Fertility and pollen tube growth in polyploid melons (Cucumis melo L.)

The high sterility of tetraploid melon (Cucumis melo L.) plants is a serious inconvenient to obtain economically useful polyploid lines. In order to study the alterations on diploid pollen tube growth and their influence on sterility, in vitro and in vivo pollen tube growth from three commercial varieties and its tetraploids was observed. Polyploid pollen grains show a lower germination percentage in vitro and a slower germination rate than haploid pollen. Furthermore, diploid pollen grains producing two or three tubes and tube branchings were observed on diploid pollen; this seems to indicate a decrease in its functionality. In vivo and in vitro pollen behaviours are quite similar, but an interaction between the pollen and the pistillar tissues was detected in vivo. In the diploid × tetraploid cross, where fruits were not obtained, pollen tubes showed a slow growth rate at the base of the pistil. The possible effects of these alterations in sterility are discussed in terms of the factors that could affect fecundation. This revised version was published online in July 2006 with corrections to the Cover Date.     

Nitrogen compound pollution associated with the use of sewage sludge compost and limestone outcrop residue under saline irrigation

Purpose

The use of composted sewage sludge and limestone outcrop residue in land rehabilitation, soil improvement, and technosol making can influence the mobility of nitrogen compounds in groundwater.

Materials and methods

This experiment analyzed this source of possible pollution under an experimental design based on the use of columns (0–30 cm) formed by both wastes and a heavy irrigation regime. Two waters of different quality (saline and non-saline) were used for irrigation. The presence of nitrate, nitrite, and ammonium in the leachates was checked.

Results and discussion

The environmental risk due to the presence of nitrogen species associated with the use of these materials was very low in general, although nitrate was the most important compound affected by the use of sewage sludge compost and saline water.

Conclusions

The combination of saline water for irrigation with the compost has to be seriously considered as a source of pollution for surface and ground waters, and the use of both resources may be a key factor to be studied (low-quality water and sewage sludge compost).

     

Contamination of the Coastal Waters of Gijón (North West Spain) by Butyltin Compounds

An innovative method for the determination of butyltin compounds in seawater samples based on the use of isotope dilution analysis has been applied to study the contamination of butyltin compounds in the Bay of Gijón (Spain) where no previous data existed. The sampling in this bay allowed the evaluation of mono-, di-and tributyltin (MBT, DBT and TBT, respectively) contamination in very different environmental compartments (harbour, marina, shipyards and enclosed and open beaches). The results showed clearly a strong influence of the type of location, the water renewal and the proximity to contaminated areas on the levels of butyltin compounds. It was found that in more than 75% of the samples the TBT values were found to be higher than the US-EPA water quality criteria of 7.4 ng L^?1 and that in 95% of the samples the concentration of TBT exceeded 1 ng L^?1 which has been reported to be a toxic level for many marine species.     

The effect of plant bioactive compounds on lamb performance,intake, gastrointestinal parasite burdens,and lipid peroxidation in muscle

Plant extracts have been widely used in animal production systems due to the benefits promoted by their bioactive components, mainly through their antioxidant effects and positive effects on animal growth, health, and meat quality. We determined whether bioactive compounds (BC) from grape (Vitis vinifera), olive (Olea europaea), and pomegranate (Punica granatum) have beneficial effects on lamb growth while controlling gastrointestinal parasitism and reducing skeletal lipid peroxidation in muscle. Fourteen lambs (4 to 5 mo of age) were housed in individual pens and assigned to two treatment groups (seven animals/group), where they received: 1) a basal diet of beet pulp:soybean meal (90:10) (CONTROL) and 2) the same diet, but containing 0.3% of BC extracted from grape, olive, and pomegranate (BNP). After 21 d of consuming their respective rations (period 1), all lambs were dosed with 10,000 L₃ stage larvae of Haemonchus contortus. Intake, production, and physiological parameters were determined before infection (period 1), after oral dosage with L₃ (period 2), and during early (period 3) and later (period 4) developmental stages of infection. Groups of animals did not differ in their ration intake or average daily gain, either before or after the infection, or in their parasitic burdens estimated through fecal egg counts (P > 0.05). Lambs under BNP showed greater feed efficiency before infection (P < 0.001), but the pattern reversed after infection. In addition, the inclusion of plant bioactives to the diet did not have an effect (P > 0.05) on blood or lipid peroxidation in muscle or on hemogram, serum concentration of haptoglobin, and immunoglobulin E. These results could be explained by low dietary doses and constrained absorption or ruminal inactivation of these compounds. Changes in feed efficiencies suggest a negative interaction between BC in the diet and parasitism, which warrants further research.