Lumber recovery and value of dead and sound black spruce trees grown in the North Shore region of Québec

Context

To increase the wood supply to its industry, the government of Québec has allocated dead and sound wood (recently dead merchantable stems, DSW) to the wood supply chain in addition to the annual allowable cut of living trees. However, DSW is often criticized by sawmillers for its perceived poor quality and lower value.

Aims

The objective of this study was to compare the lumber visual grade yield and value from live and recently dead merchantable trees in three different states of wood decomposition.

Methods

In total, 162 black spruce trees [Picea mariana (Mill.) BSP] were felled from three different sites comprising three different states of wood decomposition and three diameter classes. The state of decomposition of each standing tree was categorized following Hunter??s classification (decay stages 1 & 2, 3 and 4) and the DSW classification developed by the Government of Québec.

Results

Large trees (> 20?cm) of the Hunter 4 class have a lower value as a result of inferior quality.

Conclusion

Considering the current economic difficulties facing the forest industry and the requirements of ecosystem-based management, we recommend leaving in the forest trees that have reached such a state of deterioration.     

The fungal T-2 toxin alters the activation of primary macrophages induced by TLR-agonists resulting in a decrease of the inflammatory response in the pig

T-2 toxin is known to be one of the most toxic trichothecene mycotoxins. Exposure to T-2 toxin induces many hematologic and immunotoxic disorders and is involved in immuno-modulation of the innate immune response. The objective of this work was to evaluate the effects of T-2 toxin on the activation of macrophages by different agonists of Toll-like receptors (TLR) using an in vitro model of primary porcine alveolar macrophages (PAM). Cytotoxic effects of T-2 toxin on PAM were first evaluated. An IC₅₀ of 19.47 ± 0.9753 nM was determined for the cytotoxicity of T-2 toxin. A working concentration of 3 nM of T-2 toxin was chosen to test the effect of T-2 toxin on TLR activation; this dose was not cytotoxic and did not induce apoptosis as demonstrated by Annexin/PI staining. A pre-exposure of macrophages to 3 nM of T-2 toxin decreased the production of inflammatory mediators (IL-1 beta, TNF-alpha, nitric oxide) in response to LPS and FSL1, TLR4 and TLR2/6 agonists respectively. The decrease of the pro-inflammatory response is associated with a decrease of TLR mRNA expression. By contrast, the activation of TLR7 by ssRNA was not modulated by T-2 toxin pre-treatment. In conclusion, our results suggest that ingestion of low concentrations of T-2 toxin affects the TLR activation by decreasing pattern recognition of pathogens and thus interferes with initiation of inflammatory immune response against bacteria and viruses. Consequently, mycotoxins could increase the susceptibility of humans and animals to infectious diseases.     

New strategy for the survey of Toxoplasma gondii in meat for human consumption

Monitoring of Toxoplasma infection in animals destined for human consumption is a great challenge for human toxoplasmosis prevention. This study aimed to compare results obtained from a naturally infected population of sheep using different tests and targeting an original matrix: meat samples and muscle fluids collected at the slaughterhouse. A commercial ELISA test was performed on diaphragm fluids from 419 ovine carcasses collected at the slaughterhouse. A MAT (modified agglutination test) was performed on heart fluids obtained from the same animals. In addition, all hearts were bioassayed in mice. Serological test agreement, the relative sensitivity of ELISA MAT and mouse bioassay as well as a correlation between titres and parasite isolation probability were statistically evaluated. The overall agreement (kappa coefficient=0.64) of ELISA on diaphragm fluids and MAT on heart fluids is substantial and subsequently both tests can be used for epidemiological studies. Relative sensitivity was higher for MAT performed on cardiac fluids (90%) than ELISA on diaphragm fluid (61%). For both serological tests, relative sensitivity is lower in lambs younger than 12 months. Relative sensitivity of mouse inoculation was 42%. A significant correlation was obtained between increasing MAT titres and probability to isolate live parasite from the heart. When the fluid titre was higher than 1:16, parasites were isolated in 65% of cases. When it was lower, isolation failed in 95% of the cases. According to our results, cardiac fluids appear to be a relevant matrix for toxoplasmosis survey in meat.     

Transmission risk of human trichinellosis

Trichinella is a food-borne parasitic zoonoses and human cases are still reported in Europe mainly due to the consumption of pig meat originating from small backyard farms. Infections originating from industrialized pig farming have not been reported for decades in Europe, due to control measures to prevent the transmission of Trichinella from wildlife by indoor housing and good management practices. Therefore, risk-based monitoring programs might replace individual carcass control in industrialized pig farming as described in EU legislation SANCO 2075/2005. Transmission of Trichinella species between wildlife and the risk that may pose to humans via consumption of contaminated pork meat has not been studied quantitatively. One pathway by which human trichinellosis can occur is the rat–pig–human route. To evaluate the transmission risk though this pathway the dose responses of rat, pig, and human were studied. Experimental T. spiralis infection was performed in rats with doses of as few as 10 parasites and the data set was analysed using a newly developed dose response model that describes larvae per gram (LPG). Experimental T. spiralis infection in pig was analysed in a similar way. Furthermore nine published outbreaks of human trichinellosis were analysed to determine the dose response in humans. The risk of human trichinellosis via the rat–pig–human transmission was simulated by the Monte Carlo method. A pair of female and male parasites representing the lowest infection pressure from the environment, led to the probability of human trichinellosis by consumption of 100 g of raw pork meat equal to 5% via the studied rat–pig–human pathway. In the absence of rodent control near the farm, a low infection pressure from wildlife presents a relatively high risk of human trichinellosis via consumption of uncooked pork meat.     

The food contaminant fumonisin B1 reduces the maturation of porcine CD11R1+ intestinal antigen presenting cells and antigen-specific immune responses, leading to a prolonged intestinal ETEC infection

Consumption of food or feed contaminated with fumonisin B₁ (FB₁), a mycotoxin produced by Fusarium verticillioides, can lead to disease in humans and animals. The present study was conducted to examine the effect of FB₁ intake on the intestinal immune system. Piglets were used as a target and as a model species for humans since their gastro-intestinal tract is very similar. The animals were orally exposed to a low dose of FB₁ (1 mg/kg body weight FB₁) for 10 days which did not result in clinical signs. However, when compared to non-exposed animals, FB₁-exposed animals showed a longer shedding of F4⁺ enterotoxigenic Escherichia coli (ETEC) following infection and a lower induction of the antigen-specific immune response following oral immunization. Further analyses to elucidate the mechanisms behind these observations revealed a reduced intestinal expression of IL-12p40, an impaired function of intestinal antigen presenting cells (APC), with decreased upregulation of Major Histocompatibility Complex Class II molecule (MHC-II) and reduced T cell stimulatory capacity upon stimulation. Taken together, these results indicate an FB₁-mediated reduction of in vivo APC maturation.     

Diagnosis and outcome of a dog with iatrogenic hyperadrenocorticism and secondary pulmonary mineralization

A 6-year-old, spayed female dog was evaluated for a history of chronic coughing, excessive panting, and lethargy. Iatrogenic hyperadrenocorticism was diagnosed, and pulmonary mineralization was documented with a 99mTechnitium-methylene diphosphonate (99mTc-MDP) scan. Blood gas analysis showed hypoxia. Clinical signs resolved and blood gas values returned to normal when corticosteroid therapy was discontinued.     

Heavy Metal Lability in Porewater of Highway Detention Pond Sediments in South-Eastern France in Relation to Submerged Vegetation

Highway detention ponds can fill with sediments from runoff water loaded with traffic-related materials. Sediment disposal is problematic and various protocols are currently studied, including phytoremediation. Here we present a preliminary study on four highway detention ponds in southern France to identify key sediment characteristics. Our objectives were to characterize metal content and physicochemical properties of the sediments and to evaluate the role of charophytes, which grow spontaneously in ponds, on metal lability. Vegetated and non-vegetated areas were compared. The lability of Mn, Cu, Zn, and Pb complexes was greater in the presence of charophytes. No variation in grain size composition was observed between non-vegetated and vegetated areas. These results may be useful to implement a phytoremediation strategy using those spontaneous charophytes. Our results suggest that local factors may impact sediment characteristics: for instance, strong gusts of wind, typical of southern France climate, may blow particles (some of them not related to traffic) in and out of detention ponds.     

The effect of dietary supplementation with globin and spray-dried porcine plasma on performance,digestibility and histomorphological traits in broiler chickens

This study evaluated the effects of globin and spray-dried porcine plasma (SDPP) on growth performance, digestibility, nitrogen retention, energy retention efficiency (ERE) and intestinal morphology of broiler chickens. A total of 336-day-old male broiler chickens were reared from 1 to 40 days of age and fed 3 diets (8 replicates/diet, 14 birds/replicate) during 3 feeding phases: starter (1–12 days), grower (12–25 days) and finisher (25–40 days). Isonitrogenous diets were formulated by replacing gluten protein isolate contained in the control diet (C diet) with 2% (starter) or 1% (grower and finisher) spray-dried porcine plasma in the plasma diet (SDPP diet). The globin diet (G diet) was obtained by adding globin on the top of C diet at a dose of 0.08% for the whole rearing period. Total tract apparent digestibility (aD), nitrogen retention and ERE were assessed during the three growing phases. At 12  and 40 days of age, one bird per pen was slaughtered to sample gut, liver, spleen and bursa of Fabricius for histomorphological investigations. The SDPP diet increased body weights of chickens at 12 (+60 g; p < .001), 25 (+101 g; p < .001) and 40 days (+130 g; p = .018) of age compared to C and G diets. Also SDPP improved crude protein aD (+9.7%) and ERE (+12.3%) during the starter phase (p < .001). Dietary globin and SDPP inclusion did not affect either the gut morphology or the histopathological findings in birds at 12 and 40 days of age, despite a numerical (+6.90% and +7.40% respectively) villus height improvement in the SDPP group. Overall, these results confirm that dietary supplementation with SDPP and, to a lesser extent, with globin can improve growth performance and dietary protein and energy utilization in broiler chickens without effect on gut functionality.     

Influence of adjuvant formulation on the induced protection of mice immunized with total soluble antigen of Trichinella spiralis

Vaccination of pigs against the helminth nematode Trichinella could be a good alternative to prevent the risk of human infection. In order to develop an efficient and safe vaccine, the choice of the adjuvant is an important issue. In this study, two adjuvants were selected to prepare vaccines based on total soluble Trichinella spiralis muscle larvae (ML) antigen: Montanide ISA 70 water in oil emulsion and Montanide IMS nanoparticles. Aluminium hydroxide was used as a reference adjuvant. The immune response was checked by ELISA of parasite antigen specific IgG1 and IgE. Finally, protection induced in vaccinated mice was measured after a T. spiralis challenge by counting ML burdens. The results clearly showed an impact of adjuvants on the specific IgG1 and IgE antibody responses against T. spiralis. Differences were observed between the rates of protection induced according to the type of formulation, although the three adjuvants tested were able to enhance the humoral immune response. This work demonstrated the need to use an adjuvant to obtain a specific IgG1 and IgE responses directed against the total soluble extract of T. spiralis.