A novel enzymatic pre‐treatment improves amino acid utilization in feather meal fed to rainbow trout (Oncorhynchus mykiss)

A growth trial followed by a digestibility trial were conducted to assess the bioavailability of arginine (Arg) and amino acid digestibility of two feather meals (FeMs) and their pre‐treated counterparts (PTFeMs). Two FeMs, identified as FeM1 and FeM2, were incubated in 200% distilled water (%FeM w/w), with 0.05% of Savinase^® 16L (%FeM v/w) and 2% sodium sulphite (%FeM w/w) at 55ºC for 24 hr in a shaking incubator to produce PTFeM1 and PTFeM2 respectively. A basal diet, highly deficient in Arg (12.0 g/kg Arg) was formulated and 10 other diets were formulated to contain 13.5 or 15.0 g/kg Arg by adding increasing amounts of L‐Arg, FeMs or PTFeMs. The experimental diets were fed for 8 weeks using a standard protocol. At 13.5 g/kg Arg, the PTFeMs supported 10.5% to 11.5% higher growth rates (p < 0.05) than their untreated counterparts. The diets formulated with PTFeMs presented 3.5%–4.5% and 2.7%–5.9% higher (p < 0.05) apparent digestibility coefficients of protein when compared to the diets containing the FeM counterparts at 13.5 and 15.0 g/kg Arg respectively. The results from this study demonstrate the potential of the pre‐treatment to improve the nutritive value of FeMs in rainbow trout.     

Detection of quantitative trait loci affecting non-return rate in French dairy cattle

The purpose of this study was to map quantitative trait loci (QTL) influencing female fertility estimated by non-return rate (NRR) in the French dairy cattle breeds Prim'Holstein, Normande and Montbeliarde. The first step was a QTL detection study on NRR at 281 days after artificial insemination on 78 half-sib families including 4993 progeny tested bulls. In Prim'Holstein, three QTL were identified on Bos taurus chromosomes BTA01, BTA02 and BTA03 (p < 0.01), whereas one QTL was identified in Normande on BTA01 (p < 0.05). The second step aimed at confirming these three QTL and refining their location by selecting and genotyping additional microsatellite markers on a sub-sample of 41 families from the three breeds using NRR within 56, 90 and 281 days after AI. Only the three QTL initially detected in Prim'Holstein were confirmed. Moreover, the analysis of NRR within 56, 90 and 281 days after AI allowed us to distinguish two FF QTL on BTA02 in Prim'Holstein, one for NRR56 and one for NRR90. Estimated QTL variance was 18%, 14%, 11.5% and 14% of the total genetic variance, respectively, for QTL mapping to BTA01, BTA02 (NRR90 and NRR56) and BTA03.     

Seasonality of Reproduction in Mammals: Intimate Regulatory Mechanisms and Practical Implications

Farm mammals generally express seasonal variations in their production traits, thus inducing changing availability of fresh derived animal products (meat, milk and cheese) or performances (horses). This is due to a more or less marked seasonal birth distribution in sheep and goats, in horses but not cattle. Birth peak occurs at the end of winter-early spring, the most favourable period for the progeny to survive. Most species show seasonal variations in their ovulation frequency (presence or absence of ovulation), spermatogenic activity (from moderate decrease to complete absence of sperm production), gamete quality (variations in fertilization rates and embryo survival), and also sexual behaviour. The intimate mechanism involved is a complex combination of endogenous circannual rhythm driven and synchronized by light and melatonin. Profound and long-term neuroendocrine changes involving different neuromediator systems were described to play a role in these processes. In most species artificial photoperiodic treatments consisting of extra-light during natural short days (in sheep and goats and mares) or melatonin during long days (in sheep and goats) are extensively used to either adjust the breeding season to animal producer needs and/or to completely overcome seasonal variations of sperm production in artificial insemination centres. Pure light treatments (without melatonin), especially when applied in open barns, could be considered as non-invasive ones which fully respect animal welfare. Genetic selection could be one of the future ways to decrease seasonality in sheep and goats.     

The effect of pentaghrelin on amylase release from the rat and porcine dispersed pancreatic acinar cells in vitro

Ghrelin-28 was found to inhibit the pancreatic enzyme output in rats, although the effect of pentaghrelin has not been studied. The effect of ghrelin on pig exocrine pancreas remains largely unknown. The aim of the present study was: (1) to establish a model of porcine dispersed pancreatic acinar cells in vitro and compare it with an existing rat model, and (2) to investigate the effect of pentaghrelin on amylase release from the rat and pig pancreatic acini. The rat and porcine acinar cell preparations released amylase in response to cholecystokinin octapeptide (CCK-8) stimulation in a dose-related manner. Pentaghrelin hardly inhibited the amylase release in rat preparations (maximum inhibition with 10^− 9 M pentaghrelin). It stimulated amylase release in porcine preparations, however, no dose response was found in a range of doses between 10^− 10 and 10^− 7 M. Concluding, pentaghrelin may stimulate amylase release from porcine acinar cells through as yet unknown mechanisms.     

Colostral antibody induced interference of inactivated bluetongue serotype-8 vaccines in calves

Since its introduction into northern Europe in 2006, bluetongue has become a major threat to animal health. While the efficacy of commercial vaccines has been clearly demonstrated in livestock, little is known regarding the effect of maternal immunity on vaccinal efficacy. Here, we have investigated the duration and amplitude of colostral antibody-induced immunity in calves born to dams vaccinated against bluetongue virus serotype 8 (BTV-8) and the extent of colostral antibody-induced interference of vaccination in these calves. Twenty-two calf-cow pairs were included in this survey. The median age at which calves became seronegative for BTV was 84 and 112 days as assayed by seroneutralisation test (SNT) and VP7 BTV competitive ELISA (cELISA), respectively. At the mean age of 118 days, 13/22 calves were immunized with inactivated BTV-8 vaccine. In most calves vaccination elicited a weak immune response, with seroconversion in only 3/13 calves. The amplitude of the humoral response to vaccination was inversely proportional to the maternal antibody level prior to vaccination. Thus, the lack of response was attributed to the persistence of virus-specific colostral antibodies that interfered with the induction of the immune response. These data suggest that the recommended age for vaccination of calves born to vaccinated dams needs to be adjusted in order to optimize vaccinal efficacy.     

Enrichment of Artemia metanauplii in phospholipids and essential fatty acids as a diet for common octopus (Octopus vulgaris) paralarvae

Highly unsaturated fatty acids (HUFA), like the eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids and polar lipids (essentially phospholipids, PL) have been identified as essential nutrients for common octopus (Octopus vulgaris) paralarvae. However, they are not available in sufficient amounts in live preys as Artemia, making necessary a supplementation of these nutrients previous use. A commercial emulsion, soya liposomes, and marine and soya lecithins were used to supply HUFA and PL to Artemia metanauplii, those being regarded as suitable size preys for octopus paralarvae. Our results prove that a simultaneous enrichment in HUFA and PL is possible using enrichment diets combining HUFA‐ and PL‐rich products in short‐term (4 h) incubations. Particularly interesting was the enrichment efficiency shown by the marine lecithin, which enabled the enhancement of the PL fraction of Artemia metanauplii and, importantly, also their HUFA with a remarkable 13% DHA of total fatty acids. Marine lecithin arises as a novel enrichment diet for Artemia and more effective than some commercial products currently used in hatcheries worldwide.     

Effects of plant diversity on plant biomass production and soil macrofauna in Amazonian pastures

We examined the effect of plant diversity on plant production and soil macrofauna density and diversity. Four plants species (Arachis pintoi, an herbaceous legume; Brachiaria brizantha, a perennial grass; Leucaena leucocephala, a legume shrub; Solanum rugosum, a non-legume shrub) were used in a field experiment and communities of all combinations of one, two, three or four species were established. Plant diversity neither significantly affected density and diversity of soil macrofauna nor total plant biomass, however, the biomass of specific plants was negatively affected by plant diversity. Earthworm and ant densities were significantly higher in the presence of A. pintoi although this plant influenced neither the density of the other group nor fauna diversity. Earthworm and diplopod densities increased significantly with shoot biomass of A. pintoi. Fauna diversity increased significantly with shoot biomass (specific and total). Root biomass did not affect fauna density and diversity. Our results suggest that fauna density is affected by litter quality and that it is more affected by resource quantity than quality. Our results also confirm the importance of nitrogen fixers to ecosystem function.     

A new localized sampling method to improve grape yield estimation of the current season using yield historical data

Precision Agriculture - This paper proposes a methodology to improve grape yield sampling and yield estimation of the current season by using historical yield data. This approach is based on the...     

Use of a GnRH antagonist,antarelix, associated or not with hCG,to control ovulation in cyclic pony mares

The GnRH antagonist antarelix (Teverelix™) was administered to mares (0.01 mg/kg, i.v., twice a day) during the periovulatory period. In Experiment 1, 20 mares were divided into a treated (A3d−) and a control (Control−) group. A3d− mares received antarelix for 3 days from the day when the dominant follicle (F1) reached 32 mm (D0). In Experiment 2, 10 mares were divided into a treated (A6d+) and a control (Control+) group. A6d+ mares received antarelix for 6 days from D0 and hCG was injected in all animals (1600 IU, i.v.) on D1. Pregnancies were determined 13 days after ovulation. In both experiments, antarelix interrupted or totally abolished the LH surge. In Experiment 1, 5/10 of the A3d− mares (with maximum LH concentrations of 11.6 ng/ml at the beginning of treatment) ovulated at the same time as the Control− mares; the other five mares (with LH concentrations under 5.4 ng/ml) ovulated 13.4±0.6 days later. In Experiment 2, all the A6d+ mares ovulated at the same time as the Control+ mares. In treated mares which ovulated during the treatment, progesterone concentrations and fertility did not differ from control mares. These results demonstrate that in mares: (1) a small elevation of endogenous LH can induce ovulation, (2) ovulation can be postponed approximately 13 days after a 3-day antarelix treatment if initiated just before the preovulatory LH surge, (3) ovulation can be induced by hCG on depressed levels of endogenous LH, (4) the inhibition of the post ovulatory LH surge has no effect either on the corpus luteum or on fertility.