Comparing the intra-annual wood formation of three European species (Fagus sylvatica, Quercus petraea and Pinus sylvestris) as related to leaf phenology and non-structural carbohydrate dynamics

Monitoring cambial phenology and intra-annual growth dynamics is a useful approach for characterizing the tree growth response to climate change. However, there have been few reports concerning intra-annual wood formation in lowland temperate forests with high time resolution, especially for the comparison between deciduous and coniferous species. The main objective of this study was to determine how the timing, duration and rate of radial growth change between species as related to leaf phenology and the dynamics of non-structural carbohydrates (NSC) under the same climatic conditions. We studied two deciduous species, Fagus sylvatica L. and Quercus petraea (Matt.) Liebl., and an evergreen conifer, Pinus sylvestris L. During the 2009 growing season, we weekly monitored (i) the stem radial increment using dendrometers, (ii) the xylem growth using microcoring and (iii) the leaf phenology from direct observations of the tree crowns. The NSC content was also measured in the eight last rings of the stem cores in April, June and August 2009. The leaf phenology, NSC storage and intra-annual growth were clearly different between species, highlighting their contrasting carbon allocation. Beech growth began just after budburst, with a maximal growth rate when the leaves were mature and variations in the NSC content were low. Thus, beech radial growth seemed highly dependent on leaf photosynthesis. For oak, earlywood quickly developed before budburst, which probably led to the starch decrease quantified in the stem from April to June. For pine, growth began before the needles unfolding and the lack of NSC decrease during the growing season suggested that the substrates for radial growth were new assimilates of the needles from the previous year. Only for oak, the pattern determined from the intra-annual growth measured using microcoring differed from the pattern determined from dendrometer data. For all species, the ring width was significantly influenced by growth duration and not by growth rate, which differs from previous studies. The observed between-species difference at the intra-annual scale is key information for anticipating suitability of future species in temperate forests.     

Feed restriction followed by realimentation in prepubescent Zebu females

In the present study, the effect of restricting the feed intake for 77 days and subsequent compensatory growth for 50 days of Sindi females were evaluated. Eighteen animals with an initial age of 21 months and a mean weight of 211.7 kg were placed into three groups according to the following alimentary regimens: feed ad libitum, feed restricted to 20 % dry matter, and feed restricted to 40 % dry matter. In the feed-restriction phase, the nutrient intake decreased (P?<?0.001) with an increase in the restriction level. As a consequence, the observed decrease in ingestion and serum concentrations of total protein, albumin and globulin, urea, glucose, calcium, and phosphorus were inversely proportional (P?<?0.001) to the restriction level. Significant differences in the nutrient intake and serum concentration were not observed in the realimentation phase (P?<?0.05). When animals in the control group reached the end of the feed-restriction phase, their weights (P?<?0.05) were similar to those in the 20 % restricted group, and both obtained a final weight that was greater than that of animals in the 40 % restricted group. In the feed-restriction phase, the control group had a similar mean daily weight gain (P?>?0.05) to animals in the 20 % restricted group and (P?<?0.05) 40 % restricted group. However, in the realimentation phase, the 40 % restricted group obtained greater weight gain rates (P?<?0.05), better food conversions, and partial compensatory gains. In particular, none of the restricted groups reached the final weight of the control group. In the feed-restriction phase, ingested nitrogen, nitrogen excreted in urine and feces, nitrogen balance and retained nitrogen decreased (P?<?0.05) with an increase in the restriction level. In the realimentation phase, none of the nitrogen balance variables were influenced by the restriction level (P?<?0.05). Females in the 40 % restricted group presented better food conversion rates and greater weight gains in the realimentation phase. Based on the animals’ compensatory weight gain, a feed-restriction rate of 20 and 40 % can be adopted as a nutritional management practice for prepubescent Sindi females.     

Evaluation of Nitric Acid Extraction of Elements from Soils and Sediments in Two watersheds in East Tennessee

Determining the total elemental concentrations of soils requires a total dissolution method, in which hydrofluoric acid (HF) is commonly used. However, this method is tedious and risky due to the dangerous reagent HF. This study compared a single acid extraction technique using a nitric acid (HNO₃) extraction method to total dissolution (HF + microwave assisted aqua regia) for evaluating the total elemental concentrations in soils and sediments. The two methods were used to analyze the elemental content of soils and sediments from the Oostanaula Creek and Pond Creek watersheds in East Tennessee. Twenty-one elements (Al, Ba, Ca, Co, Cr, Cu, Fe, K, La, Li, Mg, Mn, Nd, P, S, Si, Sr, Ti, V, Zn, and Zr) were subsequently measured using inductively coupled plasma optical emission spectrometry (ICP-OES). The extraction efficiency for HNO₃ relative to the total was compared and discussed. In general, HNO₃ can extract the elements in absorbed phases and those residing in non-silicate minerals. Six elements (Ba, Co, Fe, Ca, Mn, and P) generated significant correlations between total and HNO₃ in both OC and PC watersheds. Finally, the elements were grouped according to the interrelationships of their total elemental concentrations based on the dendrogram plots, suggesting their geochemical association in soils and sediment forming minerals.     

Crude protein in low‐fish meal diets for juvenile Litopenaeus vannamei can be reduced through a well‐balanced supplementation of essential amino acids

The use of supplemental essential amino acids (EAAs) has been shown to provide an opportunity to minimize excess levels of crude protein (CP) in animal feeds. The present study investigated the effect of reducing the amount of CP in low‐fish meal diets (5%) for juvenile Litopenaeus vannamei. Four sets of diets were prepared containing (% on a fed basis, mean ± SD) 31.24 ± 0.71, 33.70 ± 0.41, 36.90 ± 0.44, and 39.63 ± 0.14% CP, with each protein level containing a total dietary methionine (Met) (Met + Cys) level of 0.56 ± 0.02 (1.07 ± 0.23), 0.71 ± 0.01 (1.22 ± 0.20), 0.88 ± 0.02 (1.38 ± 0.22), or 1.04 ± 0.02% (1.55 ± 0.18%). Shrimp of 1.00 ± 0.08 g were stocked in 84 outdoor tanks of 1 m³ at a rate of 100 shrimp/m² and raised for 75 days. Final survival ranged from 83 to 97% and was unaffected by Met content. Both survival and yield were significantly depressed when shrimp were fed the 31% CP diet. Shrimp grew at a weekly rate of between 0.79 and 0.97 g, achieving a final body weight (BW) in excess of 10.8 g. There was a significant interaction between CP and Met over BW. Shrimp fed 0.56% Met achieved the lowest BW at harvest. Increasing CP beyond 34% did not enhance BW. With a dietary Met content of 0.71%, the highest BW was achieved with 34% CP compared to other levels. There was a significant improvement in Feed Conversion Ratio (FCR) when CP was raised from 31 to 34%. Similarly, dietary Met levels above 0.71% resulted in a significantly better FCR compared to 0.56%. Our study has shown that, if dietary Met (Met + Cys) meets a minimum of 0.71% (1.22%), levels of CP could be reduced from 40 to 34% without adverse effects on shrimp performance.     

Genetic diversity of Toxoplasma gondii isolates from chickens from Brazil

Until recently, Toxoplasma gondii was considered clonal with very little genetic variability. Recent studies indicate that T. gondii isolates from Brazil are genetically and biologically different from T. gondii isolates from USA and Europe. In the present study, we retyped 151 free range chicken isolates from Brazil including 117 newly isolated samples from 11 geographically areas (Alagoas, Bahia, Ceará, Maranh?o, Paraná, Pernambuco, Rio de Janeiro, Rio Grande do Norte, S?o Paulo, Sergipe, and Rondonia) and 34 previously reported isolates from the very north (Pará) and the very south (Rio Grande do Sul). Ten PCR-RFLP markers including SAG1, SAG2, SAG3, BTUB, GRA6, c22-8, c29-2, L358, PK1, and Apico were used to genotype all isolates. Overall analysis of 151 T. gondii isolates revealed 58 genotypes. Half (29/58) of these genotypes had single isolate and the other half of the genotypes were characterized with two or more isolates. Only 1 of 151 isolates was clonal Type I strain and 5 were clonal Type III strains. Two isolates had mixed infections. Clonal Type II strain was absent. One strain was Type II at all loci, except BTUB. The results confirm high genetic diversity of T. gondii isolates from Brazil.     

Identification of unreported putative new bovine papillomavirus types in Brazilian cattle herds

The amplification by degenerate primers FAP59/FAP64 and sequencing allowed the detection of 15 putative new BPV types in cutaneous warts as well as in healthy skin. Four of these isolates were recently recognized as new BPV types (BPV-7, -8, -9, and -10) after determination of their complete genome sequences. In Brazil, investigations involving the definition of BPV types present in skin warts are still rare. The aim of the current study was to identify the BPV types associated with cutaneous papillomatosis observed in Brazilian cattle herds. Twenty-two cutaneous papilloma specimens were submitted to PCR assay employing the FAP primer pair. All PCR products with approximately 480 bp were submitted to direct sequencing. Cloning was performed for the amplicons which prior analysis revealed as putative new BPV types. From 16 cutaneous lesions, BPV-1, -2, and -6 were identified in two, six, and eight papilloma specimens, respectively. In addition, four putative new BPV types were identified in other six skin warts, and then designated as BPV/BR-UEL2 to -5. The detection of the BPV-1, -2, and -6 types in skin wart specimens supports the existence of these BPV types throughout the Brazilian cattle herd. In addition, the identification of four putative new BPV types is the first report of the presence of different BPV types in the American continent.     

Effect of suckling period on calf growth and milk yield of Zebu cows

Eighteen multiparous Zebu cows in their third lactation and their calves were randomly allocated to three suckling periods, up to 3, 4 or 5 months of age of the calf. The cows were individually fed natural hay, cottonseed cake and molasses. At 2 months of age, all calves were separated from their mothers, and were offered cottonseed cake mixed with molasses and Mucuna hay individually. The calves stimulated milk ejection by suckling 30 seconds and suckled the residual milk for 45 minutes after milking. The dry matter intake of cows (3.68, 3.29 and 3.31% of body weight) and calves (2.88, 2.80 and 2.55% of body weight) for suckling up 3, 4 and 5 months of age, respectively, was not significantly affected by treatment and neither was the growth rate of the calves (178, 157 and 149 g/d for 3, 4 or 5 months suckling period, respectively). Cows suckling their calves up to 5 months had significantly higher milk yield and higher amount of saleable milk (1.97, 2.93 and 3.69 kg/cow/d for 3, 4 and 5 months suckling period, respectively). The fat content of the milk decreased with increasing length of the suckling period while the protein content was not affected. In conclusion, a suckling period of 5 months resulted in higher total milk production and higher amount of saleable milk but did not seem to have any effect on calf growth when the calves were supplemented.     

The effect of dietary supplementation with 9-cis:12-trans and 10-trans:12-cis conjugated linoleic acid (CLA) for nine months on serum cholesterol, lymphocyte proliferation and polymorphonuclear cells function in Beagle dogs

Conjugated linoleic acids (CLA), 9-cis:11-trans and 10-trans:12-cis, have been shown to be able to modify some immune cells parameters and plasma lipids in a variety of experiment models. Since lymphocytes and polymorphonuclear cells (PMNC) have a large spectrum functions in the immune response, the knowledge in this field has to be expanded. Beagle dogs were fed a control diet or a CLA supplemented diet for nine months. Blood was collected for biochemical analysis and lymphocyte and PMNC isolation. PMNC were assayed for lysosome content, phagocytic activity and superoxide anion production. A lymphocyte proliferation capacity assay was done. The CLA fed dogs had a 34% reduction in total cholesterol (P < 0.05), 28% in LDL (P < 0.05) and 28% non-HDL-cholesterol (P < 0.05). Neither of the PMNC parameters evaluated demonstrated significant alteration. Lymphocytes from CLA group increased by 45% their mitotic capacity (P < 0.05). Our study demonstrates that CLA can successfully modify the lipid profile of dogs (monogastrics) when fed at reasonable levels, but did not significantly alter inflammatory function as would generally predicted. Further, we had some indication that CLA modulated T cell responsiveness.     

Impact of climate change on the small mammal community of the Yukon boreal forest

Long‐term monitoring is critical to determine the stability and sustainability of wildlife populations, and if change has occurred, why. We have followed population density changes in the small mammal community in the boreal forest of the southern Yukon for 46 years with density estimates by live trapping on 3–5 unmanipulated grids in spring and autumn. This community consists of 10 species and was responsible for 9% of the energy flow in the herbivore component of this ecosystem from 1986 to 1996, but this increased to 38% from 2003 to 2014. Small mammals, although small in size, are large in the transfer of energy from plants to predators and decomposers. Four species form the bulk of the biomass. There was a shift in the dominant species from the 1970s to the 2000s, with Myodes rutilus increasing in relative abundance by 22% and Peromyscus maniculatus decreasing by 22%. From 2007 to 2018, Myodes comprised 63% of the catch, Peromyscus 20%, and Microtus species 17%. Possible causes of these changes involve climate change, which is increasing primary production in this boreal forest, and an associated increase in the abundance of 3 rodent predators, marten (Martes americana), ermine (Mustela ermine) and coyotes (Canis latrans). Following and understanding these and potential future changes will require long‐term monitoring studies on a large scale to measure metapopulation dynamics. The small mammal community in northern Canada is being affected by climate change and cannot remain stable. Changes will be critically dependent on food–web interactions that are species‐specific.