Trichostrongylus colubriformis infection damages intestine brush board cells and could negatively impact postabsorptive parameters of Santa Ines lambs.

This study aimed to evaluate histological, digestive and postabsorptive physiological parameters in Santa Ines lambs infected with Trichostrongylus colubriformis and fed different levels of phosphorus. Therefore, eighteen Santa Ines, castrated male, six-month old, healthy lambs (initial body weight 22.4 ± 2.7 kg) were distributed in one of four treatments arranged in a 2 × 2 split-plot arrangement: Sufficient dietary P level and uninfected (SPui; n = 4), Sufficient dietary P level and infected (SPi; n = 5), Deficient dietary P level and uninfected (DPui; n = 4), Deficient dietary P level and infected (DPi; n = 5). Infected lambs received, orally, a single pulse dose of 40.000 T. colubriformis infective larval stage (L3). Animals were fed Tifton 85 hay (Cynodon ssp.; 60%), and cassava meal and maize gluten meal (40%). Measurement of nutrient apparent digestibility and nitrogen metabolism were performed in individual metabolic stalls. To achieve the trial results, it was measured methane emissions in respiratory chambers, urine purine derivatives, ruminal short-chain fatty acids (SCFA), histological cuts of duodenal mucosal tissues and passage rates fluxes, analyzed by external (Yb, Cr, and Co) and internal (iNDF) markers. Statistical procedures were performed in R studio. The fixed main effects of treatment and the interactions were tested by ANOVA, and means compared by Duncan's test at 5% significance. Apparent digestibility was not affected by treatments, however, nitrogen retained decreased (P < 0.01) and urinary nitrogen losses increased (P < 0.01) in infected animals. Small intestine digesta content, empty segment weight, and length were higher in infected animals (P < 0.05). Passage rate was not majorly affected by infection or dietary P levels. Methane emissions, SCFA concentrations, and purine derivative excretion were also not affected by treatments. Regarding the histology, the vilosity weight (P < 0.05), and crypt depth (P < 0.01) decreased in infected animals. In conclusion, T. colubriformis infection can damage intestinal mucosa and affect nitrogen metabolism, but did not affect the digesta transit, and nutrient digestibility. The P dietary levels did not promote any modification in GIT physiological parameters tested in this study.

Ovarian activation delays in peripubertal ewe lambs infected with Haemonchus contortus can be avoided by supplementing protein in their diets.

BACKGROUND: The ewe lamb nutritional and physiological state interfere with the ovarian environment and fertility. The lack or excess of circulating nutrients reaching the ovary can change its gene expression. A protein deficiency in the blood caused by an Haemonchus contortus abomasal infection is detrimental to the organism's development during puberty. The peripubertal period is a time of intensive growth that requires a high level of nutrients. An essential feature controlling pubertal arousal and female reproductive potential is ovarian follicle growth activation. Protein supplementation improves the sheep's immune response to helminthic infections. We aimed to determine if supplementing protein in infected ewe lambs' diet would impact the ovarian environment leading to earlier ovarian follicle activation than in infected not supplemented animals. METHODS: We fed 18 Santa Ines ewe lambs (Ovis aries) - bred by the same ram - with either 12% protein (Control groups) or 19% protein (Supplemented groups) in their diets. After 35 days of the diet, they were each artificially infected or not with 10,000 Haemonchus contortus L3 larvae. Following 77 days of the diet and 42 days of infection, we surgically collected their left ovaries and examined their genes expression through RNA sequencing. RESULTS: We found that protein supplementation in infected animals led to an up-regulation of genes (FDR p-values < 0.05) and biological processes (p-value cut-off = 0.01) linked to meiotic activation in pre-ovulatory follicles and primordial follicle activation, among others. The supplemented not infected animals also up-regulated genes and processes linked to meiosis and others, such as circadian behaviour. The not supplemented animals had these same processes down-regulated while up-regulated processes related to tissue morphogenesis, inflammation and immune response. CONCLUSION: Diet's protein supplementation of peripubertal infected animals allowed them to express genes related to a more mature ovarian follicle stage than their half-sisters that were not supplemented. These results could be modelling potential effects of the interaction between environmental factors, nutrition and infection on reproductive health. When ovarian activation is achieved in a timely fashion, the ewe may generate more lambs during its reproductive life, increasing sheep breeders' productivity.

The effect of Haemonchus contortus and Trichostrongylus colubriforms infection on the ruminal microbiome of lambs.

We evaluated Haemonchus contortus (HC) and Trichostrongylus colubriformis (TC) infection on the ruminal microbial community of Santa Ines lambs to better understand the pathophysiology of parasite infections and the interactions among gastrointestinal nematodes and gut resident microbiota. In this study, 18 six months of age lambs were maintained for 34 days in individual pens divided into three treatments that included animals infected with HC and TC, and control (infection-free). Haematological, ruminal parameter and microbial nitrogen absorbed by pune derivatives, as well as enteric methane emission (CH4), were analysed, and the rumen microbial taxonomic and functional profile assessed by shotgun metagenomics. The analysis showed that total protein, albumin, urea, and butyrate level were lower in animals infected by both parasites, while HC infection also decreased the haemoglobin level. Both infected groups (TC and HC) increased the enteric methane emission (CH4). TC and HC infections increased the diversity and richness of functional microbial genes. Most alterations in the rumen microbiome composition of infected groups are associated with the suppression of microbes involved in microbial homeostasis maintenance and expansion of the archaeal community in the infected animals. Infection led to an increased abundance of nitrogen, amino acid, protein, and energy metabolism genes. Overall, TC and HC infection increased the enteric methane emission, negatively affected taxon's responsible for maintenance de rumen homeostasis and modulated some important genes related to protein and energy metabolism.

Potential use of cassava by-product as ruminant feed.

Cassava (Manihot esculenta Crantz) bagasse is the by-product from industry (BCI), generated during manufacturing of cassava flour; this material has significant amounts of carbohydrates consisting in a potential energy source for ruminants. We hypothesized that the inclusion of BCI in the diets may lead to fermentation parameters equivalent to those of conventional feedstuff such as tropical grasses or grains; therefore, we aimed to evaluate ruminal fermentation parameters of BCI in in vitro conditions. Three different substrates were prepared: 100% BCI (BCI diet), 100% tifton (Cynodon spp.) hay (CTL diet), and 50% tifton hay +50% BCI (THB diet). Ruminal fermentation parameters of these diets were evaluated in in vitro gas production assays. In a 24-h incubation, increased values for total gas production, organic matter degradability, and methane production were observed for BCId and THB as compared to CTL (p < 0.05), while neutral THB showed the highest value for neutral detergent fiber degradability (p < 0.05). Fermentation profile was evaluated in a 48-h assay: shorter lag time as well as increased gas production potential and fractional fermentation rate were observed for the BCId and THB as compared to CTL (p < 0.05). Our results suggested that by-product from cassava industry is a suitable feed for ruminant production, providing desirable in vitro ruminal fermentation performance and organic matter degradability.

Gestational and lactational exposure to gossypol alters the testis transcriptome.

BACKGROUND: Reproductive capacity can be altered by challenges experienced during critical periods of development, including fetal development and early neonatal life. Gossypol is a polyphenolic compound, commonly found in cotton seeds, that impairs male reproduction. Here, we investigated whether the exposure to gossypol in utero and during lactation alters male reproductive function in sheep. From conception until 60 days postpartum, ewes were randomly assigned to a control diet or a gossypol-rich diet based on cottonseed. Lamb testicles were removed at 60 days of age and subjected to RNA-sequencing. RESULTS: Lambs derived from the maternal cottonseed diet showed significantly lower growth and lower testis weight as a proportion of the total body weight, and reduced testosterone levels. In addition, the testis transcriptome was significantly altered by the maternal cottonseed diet. Most of the altered genes are directly implicated in testis development and sperm biology, cell communication, iron ion metabolism, calcium homeostasis and signaling, among other functions. Interestingly, network analysis revealed that exposure to gossypol significantly disturbed coexpression patterns among spermatogenesis-related genes, suggesting a disruption in coregulation mechanisms. CONCLUSIONS: Our findings provide evidence that maternal exposure to gossypol alters male reproductive function in the offspring, with potential lasting or lifelong negative consequences.

Fibrolytic enzymes improving in vitro rumen degradability of tropical forages.

During specific times of the year, especially dry seasons, tropical forages typically have poor nutritional value due to high contents of neutral and acid detergent fibres, and low crude protein in their composition, which may reduce productivity of ruminant livestock production and lead to increased enteric methane (CH4 ) emissions per unit of generated product in forage-bases systems. In order to increase fibre degradability and the efficiency of energy utilisation from low-quality forages, exogenous fibrolytic enzymes have been studied. In this assay, we evaluated the effects of increasing dose levels of fibrolytic enzymes extract (FEE) produced by Trichoderma reesei on in vitro rumen organic matter degradability, fermentation parameters, total gas and CH4 production of tropical forages. Forage samples were analysed for their bromatological composition, and enzyme activity from FEE was performed for xylanase and endoglucanase. The in vitro gas production technique was used in a 5 × 3 factorial arrangement with five FEE dose levels (0, 5, 50, 500 and 5,000 µl) and three substrates (Cynodon spp., Panicum maximum and Cenchrus ciliaris L.). The highest dose level of FEE increased degradability, total gas and CH4 production in all substrates (p < .05). Butyrate concentration also increased while acetate:propionate ratio and pH decreased with the addition of FEE (p < .05). These results indicated that the use of fibrolytic enzymes can be a reliable strategy to improve degradability of low-quality forages, contributing to the sustainability and intensification of livestock production in tropical countries.

Effects of Acacia mearnsii supplementation on nutrition, parasitological, blood parameters and methane emissions in Santa Inês sheep infected with Trichostrongylus colubriformis and Haemonchus contortus.

Gastrointestinal nematodes are a main problem for ruminant production, reducing animal performance and increasing environmental impact per unit of animal product generated. Tannin supplementation may lead to positive results regarding aspects such as parasitic infections and methane (CH4) emissions. Therefore, the objective of this experiment was to evaluate the effects of the condensed tannins (CT) extract made of powdered Acacia mearnsii bark (PAB) on nutrition, parasitic status and CH4 emissions in sheep artificially infected with Trichostrongylus colubriformis and Haemonchus contortus. Twenty 10-month old Santa Inês lambs (24.7 ± 3.14 kg of initial body weight) were used in a 50-day trial. Animals were divided in four treatment groups according to parasitic infection and PAB supplementation: two control groups without infections, one without PAB (C-) (n = 4) and one with PAB (C+) (n = 4); two infected groups, one without PAB (I-) (n = 6) and another receiving PAB (I+) (n = 6). Initially, animals were kept in individual pens where they were fed ad libitum chopped tifton 85 hay (Cynodon spp.) and 210 g/animal/day of concentrate. On the first day of experiment, animals of I- and I+ groups were artificially infected with infective larvae (L3) of T. colubriformis and H. contortus. Lambs were weighed fortnightly to calculate average daily body weight gain (ADG). Blood and faeces samples were also collected in the same moment of weighing for the evaluation of blood parameters and faecal egg count (FEC) respectively. After 40 days of experiment, measurements of CH4 emissions in small chamber system started and following that, apparent total tract digestibility (ATTD) assay was carried out in metabolic cages. In the end of experimental period (50 days), lambs were slaughtered and samples of abomasum and small intestine content were collected for worm count, identification, and eggs/female count. No significant (p > 0.05) treatment effects were verified for ADG, ATTD and worm count. Blood parameters were affected in both infected groups (p < 0.05) from the 28th experimental day onwards, when these animals started to show reduced red blood cells, haemoglobin and packed cell volume when compared to C- and C+. Decreased FEC was verified in I+ when compared to I- and also, H. contortus eggs/female worm for I+ was lower than for I- (p < 0.05). Both infected groups showed higher CH4 emissions than the control groups (p < 0.05). Results highlighted the anthelmintic potential of PAB and indicated methanogenic effect of parasitic nematode infections.

Fatty acid profile and carcass characteristics in castrated and uncastrated hair lambs.

The aim of this study was to investigate the effects of castration on carcass characteristics and fatty acid profile of visceral fat and meat from lambs. Eighteen six-month-old Santa Inês male lambs (18.9 ± 2.4 kg of body weight (BW)) were used. Animals were assigned to two treatments according to their sexual condition: uncastrated (U) or castrated (C). During a 98-day experimental period, animals were kept on an Andropogon gayanus grass pasture area of 1 ha and supplemented with 200 g/animal/day of concentrate mixture. Water and mineral salt were available ad libitum. The lambs were weighed fortnightly, and at the last day of the trial, they were slaughtered for evaluation of carcass characteristics and fatty acids profile of perirenal fat and longissimus lumborum muscle samples. Castrated lambs showed higher BW than U during most part of the experiment (p < 0.05). Fat deposition was higher in C lambs as evidenced by their increased carcass fat cover. Meat from U lambs showed lower content of C16:0 and higher polyunsaturated fatty acids (PUFA) (p < 0.05) than that from C (U, 14.3 and C, 10.5%). Conjugated linoleic acid (CLA) content was not affected by castration (p > 0.05) (U, 0.74 and C, 0.76%). The cis-9, cis-12 C18:2n-6 (U, 10.6 and C, 6.86%) fatty acid and the PUFA:SFA (saturated fatty acids) ratio (U, 0.36 and C, 0.25) were higher in the muscle of U lambs (p < 0.05), indicating that the meat from U animals may provide more benefits to human health than that of C.

Phosphorus kinetics in lambs experimentally infected with Trichostrongylus colubriformis with the use of 32P.

This study was conducted to evaluate the metabolism and phosphorus (P) kinetics in lambs experimentally infected with Trichostrongylus colubriformis using the isotope dilution technique and modelling. Fifteen male lambs (21.1 ±â€¯1.50 kg) of the Santa Inês hair breed of approximately six months old, distributed in the treatments infected (I, n = 8) and control (C, n = 7) were used. The infected lambs received serial infections with 5000 T. colubriformis larvae, three times per week, for 3 weeks (45 000 T. colubriformis total larvae). After 66 days of the last inoculation of infective larvae, 6.6 MBq of 32P were injected in each lamb to evaluate the P kinetics. Blood, faeces and urine samples were collected in the following seven days and the slaughter of lambs were carried out on the last day in order to collect bone and soft tissues (Liver, kidney, heart and muscle) samples. To analyse P flows, the biomathematical model with four compartments (C1 - gastrointestinal tract, C2 - plasma, C3 - bone and C4 - soft tissue) was used. Similar P intake (VI) between treatments (C and I) was verified. Lower absorption of endogenous (Vaf) and dietary P (Vaa), as well as, lower amount of endogenous P (from saliva) that reaches the gastrointestinal tract (VIT), consequently, higher excretion of dietary P (VFD) were verified in infected lambs (P < 0.1). Additionally, in infected lambs, the P bioavailability was lower compared to control lambs. With the lower absorption (VaT) of P in infected lambs, there was, consequently, lower distribution to bones and soft tissues (VeD2) and lower P deposition in the bones (VO+D). It was concluded that P metabolism of lambs infected with T. colubriformis was altered, with reduced intestinal absorption and bioavailability, increased faecal loss and reduced P flow to the bone.

Exploring the sheep rumen microbiome for carbohydrate-active enzymes.

The rumen is a complex ecosystem enriched for microorganisms able to degrade biomass during the animal's digestion process. The recovery of new enzymes from naturally evolved biomass-degrading microbial communities is a promising strategy to overcome the inefficient enzymatic plant destruction in industrial production of biofuels. In this context, this study aimed to describe the bacterial composition and functions in the sheep rumen microbiome, focusing on carbohydrate-active enzymes (CAE). Here, we used phylogenetic profiling analysis (inventory of 16S rRNA genes) combined with metagenomics to access the rumen microbiome of four sheep and explore its potential to identify fibrolytic enzymes. The bacterial community was dominated by Bacteroidetes and Firmicutes, followed by Proteobacteria. As observed for other ruminants, Prevotella was the dominant genus in the microbiome, comprising more than 30 % of the total bacterial community. Multivariate analysis of the phylogenetic profiling data and chemical parameters showed a positive correlation between the abundance of Prevotellaceae (Bacteroidetes phylum) and organic matter degradability. A negative correlation was observed between Succinivibrionaceae (Proteobacteria phylum) and methane production. An average of 2 % of the shotgun metagenomic reads was assigned to putative CAE when considering nine protein databases. In addition, assembled contigs allowed recognition of 67 putative partial CAE (NCBI-Refseq) representing 12 glycosyl hydrolase families (Pfam database). Overall, we identified a total of 28 lignocellulases, 22 amylases and 9 other putative CAE, showing the sheep rumen microbiome as a promising source of new fibrolytic enzymes.

Performance of sheep grazing in pastures of Brachiaria decumbens, Brachiaria brizantha, Panicum maximum, and Andropogon gayanus with different protodioscin concentrations.

Brachiaria spp. are the most important grasses for ruminants in central-western Brazil. However, the use of these pastures is limited by their toxicity due to steroidal saponins. This experiment was conducted for 60 days to demonstrate the resistance of sheep raised on Brachiaria spp. pastures to steroidal saponin poisoning. The experiment was composed by 48 animals randomly divided into four groups (n = 12). Among them, 32 4- to 5-month-old castrated male crossbred Santa Inês sheep, originating from flocks that had been grazing on Brachiaria spp. for more than three consecutive years, and 16 were non-adapted (naïve) sheep from flocks that never had prior contact with pastures of Brachiaria spp. were randomly divided into four groups. Each of the four experimental groups was composed by eight adapted and four non-adapted animals. The four experimental groups were introduced into paddocks, each of which contained a single grass: either Brachiaria decumbens, Brachiaria brizantha, Panicum maximum, or Andropogon gayanus. The addition of the naïve sheep to the groups was designed to detect pastures' toxicity to naïve sheep and to adjust the stocking rate to optimize the use of forage. The weight gains of sheep grazing on B. decumbens, B. brizantha, and P. maximum were similar; however, the A. gayanus group showed lower weight gains compared with the other groups (P < 0.05). The mean serum activities of γ-glutamyltransferase in the sheep grazing on B. decumbens were higher than those in the sheep from the other groups. No significant differences among the groups were found in aspartate aminotransferase, creatinine, albumin, or total protein serum concentrations. No clinical signs were observed in the adapted sheep in any of the pastures. Of the four non-adapted sheep introduced into the B. decumbens pasture, two showed clinical signs of steroidal saponin poisoning, and one died. No clinical signs were observed in the non-adapted sheep in the other pastures. The saponin (protodioscin) concentrations in the pastures varied from 3.3 to 12.2 g/kg DM in B. decumbens, from 2.8 to 9.1 g/kg DM in B. brizantha, and from 1 to 1.5 g/kg DM in A. gayanus. No saponins were found in P. maximum. It is concluded that sheep from flocks reared in pastures of B. decumbens and B. brizantha were resistant to steroidal saponin poisoning and showed similar weight gains to those of sheep grazing in other tropical pastures.

Methane emission of Santa Inês sheep fed cottonseed by-products containing different levels of gossypol.

The aim of this study was to evaluate the methane (CH4) emission of Santa Inês sheep fed cottonseed by-products, verifying if the gossypol content of these feedstuffs affects CH4 emission. Twelve late-lactating Santa Inês sheep (44.8 ± 7.5 kg body weight (BW)) were allocated in metabolic cages for an experimental period of 19 days, 14 days for adaptation and 5 days for measuring CH4 emission and dry matter intake (DMI). The animals were divided into four treatments, established in accordance with the cottonseed by-product used in concentrate formulation: Control (CON - no cottonseed by-product), Whole cottonseed (WCS), Cottonseed cake (CSC), and Cottonseed meal (CSM). The free gossypol level of the concentrates were 0, 1,276, 350, and 190 ppm for CON, WCS, CSC, and CSM, respectively. Also, the animals received Cynodon dactylon cv. Coast Cross hay, water, and mineral salt ad libitum. The ether extract content of the diets was balanced between treatments by including soybean oil in concentrates. The technique used to measure the CH4 emission was the sulfur hexafluoride (SF6) tracer technique, and the gas samples collected were quantified by analysis in gas chromatography system. The CH4 emission was evaluated considering the daily emission (g CH4/day); DMI (g CH4/kg DMI); and BW (g CH4/kg BW). No statistical difference was found (P > 0.05) between treatments for DMI and CH4 parameters. In the regression analysis, no significant relation (P > 0.05) between gossypol content and CH4 emission was observed. These results suggest that gossypol does not affect rumen methanogenesis.

Interaction between methanotrophy and gastrointestinal nematodes infection on the rumen microbiome of lambs.

Complex cross-talk occurs between gastrointestinal nematodes and gut symbiotic microbiota, with consequences for animal metabolism. To investigate the connection between methane production and endoparasites, this study evaluated the effect of mixed infection with Haemonchus contortus and Trichostrongylus colubriformis on methanogenic and methanotrophic community in rumen microbiota of lambs using shotgun metagenomic and real-time quantitative PCR (qPCR). The rumen content was collected from six Santa Inês lambs, (7 months old) before and after 42 days infection by esophageal tube. The metagenomic analysis showed that the infection affected the microbial community structure leading to decreased abundance of methanotrophs bacteria, i.e. α-proteobacteria and ß-proteobacteria, anaerobic methanotrophic archaea (ANME), protozoa, sulfate-reducing bacteria, syntrophic bacteria with methanogens, geobacter, and genes related to pyruvate, fatty acid, nitrogen, and sulfur metabolisms, ribulose monophosphate cycle, and Entner-Doudoroff Pathway. Additionally, the abundance of methanogenic archaea and the mcrA gene did not change. The co-occurrence networks enabled us to identify the interactions between each taxon in microbial communities and to determine the reshaping of rumen microbiome associations by gastrointestinal nematode infection. Besides, the correlation between ANMEs was lower in the animal's postinfection. Our findings suggest that gastrointestinal parasites potentially lead to decreased methanotrophic metabolism-related microorganisms and genes.

Exploring AMH levels, homeostasis parameters, and ovarian primordial follicle activation in pubertal infected sheep on a high-protein diet.

"Exploring AMH Levels, Homeostasis and Primordial Follicle Activation in Pubertal Infected Sheep on a High Protein Diet ". The first activation wave of ovarian primordial follicles is part of the onset of puberty and fertility. Abomasal helminth infection may cause an undesirable delay in puberty manifestation. Helminth-infected animals demand a higher amount of protein in their diet to repair the damage caused by the parasite in sheep's tissues, replenish the blood losses, and build the host's immune response. Helminths become resistant to drug therapy shortly after being exposed to a new treatment. Besides, there is the possibility of contamination by anthelmintic drugs in ovine products, possibly affecting human health and the environment. This study's objective was to evaluate if ovarian and clinical parameters can be improved by supplementing their diet with protein, offering a more sustainable management approach than relying on anthelmintic usage. We used a 2 × 2 factorial model where eighteen ewe lambs (Ovis aries) between 6 and 7 months old - born to the same ram - were fed one of two diet protein levels (12% or 19%). After 35 days on this diet, they were infected or left uninfected with 10,000 Haemonchus contortus L3 larvae. We evaluated Anti-Mullerian Hormone serum levels, blood cells and biochemical parameters at four different time points. Following 42 days of infection and 77 days on the diet, the lambs had their left ovaries removed, and we examined ovarian morphometrics through histological analysis. The groups Supplemented Protein-Infected(n = 5), Control Protein- Infected(n = 5), Supplemented Protein-Not Infected (n = 4) and Control Protein-Not Infected (n = 4) did not differ in their bodyweight gain. In the factorial ANOVA analysis examining the relationship between plasma protein, diet, and infection, the protein level of the diet showed significance (p = 0.02). Primordial follicle size varied with the interaction between diet and infection (p < 0.05), and oocyte size was affected by the level of protein in the diet (p = 0.047). Additionally, to understand how all homeostasis parameters relate to the primordial follicle and oocyte size, we applied an explanatory linear mixed model. In conclusion, serum AMH levels remained stable despite the infection and variations in diet protein levels, indicating its reliability as a marker for ovarian reserve in pubertal sheep. The number of blood cells, biochemical parameters, and primordial follicle activation were affected by both diet and infection.

Thermographic evaluation of climatic conditions on lambs from different genetic groups.

In production systems the characterization of genetic resources in relation to their capacity to respond to environmental conditions is necessary. The objective of this study was to evaluate the use of infrared thermography for separation of animals from different genetic groups and determine which phenotypic traits are important for climatic adaptation. A total of 126 suckling lambs from four different genetic groups (Santa Inês--SI, Bergamasca--B, Bergamasca X Santa Inês--BS, and Ile de France X Santa Inês--IL) were used. The animals were divided into two groups, one housed and another in an outside paddock. Thermograph photographs were taken at four-hour intervals over three full days. Temperatures of the nose, skull, neck, fore and rear flanks and rump were measured, as well as coat depth, the density and length of hairs, reflectance and color. The daily temperature range during the experimental period was more than 20°C, with animals experiencing heat (12 h to 15 h) and cold (24 h to 4 h) stress. The three main phenotypic traits that influenced genetic group separation were hair density, height of coat, and length of hairs. Thermograph temperatures were able to detect different responses of the genetic groups to the environment. Therefore, infrared thermography is a promising technique to evaluate the response of animals to the environment and to differentiate between genetic groups.

Multivariate analysis of heat tolerance characteristics in Santa Inês and crossbred lambs in the Federal District of Brazil.

Heat tolerance is an important trait for deciding on which genetic resource to use on farms in tropical regions. Three genetic groups of lambs were evaluated by physical and physiological parameters related to adaptation and multivariate analyses used to test if these traits were efficient in separating the genetic groups and which traits were more important in this separation. Crossbred lambs were more similar to each other than to Santa Inês, in general; but individually there was an overlap between Ile de France and Santa Inês lambs. Size traits had higher canonical correlation with physiological variables, while rectal temperature, heart rate, and hemoglobin were more highly correlated with physical traits. Error rates using only physiological traits were high, suggesting that these are inefficient in separating groups of lambs for heat tolerance, while separation with physical traits was more efficient.

Tropical tanniniferous legumes used as an option to mitigate sheep enteric methane emission.

This study presents the first results from Brazil using SF(6) tracer technique adapted from cattle to evaluate the capability of condensed tannin (CT) present in three tropical legume forages, Leucaena leucocephala (LEU), Styzolobium aterrimum (STA), and Mimosa caesalpiniaefolia Benth (MIM) to reduce enteric CH(4) production in Santa Inês sheep. Twelve male lambs [27.88 ± 2.85 kg body weight (BW)] were allocated in individual metabolic cages for 20-day adaptation followed by 6 days for measuring dry matter intake (DMI) and CH(4) emission. All lambs received water, mineral supplement, and Cynodon dactylon v. coast-cross hay ad libitum. The treatments consisted of soybean meal (710 g/kg) and ground corn (290 g/kg) [control (CON)]; soybean meal (150 g/kg), ground corn (30 g/kg), and Leucaena hay (820 g/kg) (LEU); soybean meal (160 g/kg), ground corn (150 g/kg), and Mucuna hay (690 g/kg) (STA); and soybean meal (280 g/kg), ground corn (190 g/kg), and Mimosa hay (530 g/kg) (MIM); all calculated to provide 40 g/kg CT (except for CON). DMI (in grams of DMI per kilogram BW per day) was lower for LEU (22.0) than CON (29.3), STA (31.2), and MIM (31.6). The LEU group showed emission of 7.8 g CH(4)/day, significantly lower than CON (10.5 g CH(4)/day), STA (10.4 g CH(4)/day), and MIM (11.3 g CH(4)/day). However, when the CH(4) emission per DMI was considered, there were no significant differences among treatments (0.37, 0.36, 0.33, and 0.35 g CH(4)/g DMI/kg BW/day, respectively, for CON, LEU, STA, and MIM). The sheep receiving STA had shown a tendency (p = 0.15) to reduce methane emission when compared to the CON group. Therefore, it is suggested that tropical tanniniferous legumes may have potential to reduce CH(4) emission in sheep, but more research is warranted to confirm these results.

Effect of Brazilian red propolis administration on hematological, biochemical variables and parasitic response of Santa Inês ewes during and after flushing period.

Brazilian red propolis was administered orally to Santa Inês ewes, and evaluation was made of general health and hematological, biochemical, and parasitic responses during and after flushing. Thirty mature, nonlactating, nonpregnant Santa Inês ewes (40 ± 2 kg and 2.5 years old) were grazing tropical pasture (Brachiaria decumbens and Pennisetum purpureum) and, as flushing after synchronization, were supplemented with a concentrate-roughage mixture at a rate of 4 % body weight (BW). Ewes were divided according to BW and fecal egg count (FEC) into two groups (n = 15 each): control and propolis that received propolis ethanolic extract at rates of, respectively, 0 and 3 g/ewe/day. The treatments lasted 21 days until the end of flushing period. BW and body condition score (BCS) were recorded, and blood and fecal samples were taken weekly for 8 weeks. Mean values of BW and BCS were not (P > 0.05) affected by propolis administration. Propolis increased (P < 0.01) total leukocytes (WBC), but no significant differences were observed for other hematological parameters. Propolis increased (P < 0.01) total protein and globulin concentrations and decreased (P < 0.01) triglycerides, glutamate oxaloacetate transaminase, and glutamate pyruvate transaminase. Propolis decreased (P < 0.05) FEC. Propolis administration had good impact on ewe health and may be a promising feed additive during critical periods such as flushing.

Computed tomography and radioactive 32P detected phosphorus impairment in metabolism, reduced bones density and animal performance caused by mixed infection of Haemonchus contortus and Trichostrongylus colubriformis in sheep.

Phosphorus (P) is one of the main minerals present in the animal body and exerts crucial functions in the organism. P is present at all cell membranes and integrates the structure of bones, being necessary its supplementation in ruminants due to the deficiency of this mineral in the pastures. One of the principal factors that compromise its metabolization are gastrointestinal nematodes (GIN). Thus, the objective of this study was evaluate the performance and metabolism of P through its distribution in the animal body, density of bones and muscles, dynamic fluxes, biological availability and half live of P, concentration of P in tissues and bones of lambs simultaneously infected with the most prevalent GIN to sheep, in tropical or subtropical areas, (Haemonchus contortus and Trichostrongylus colubriformis) using the isotopic dilution technique with 32P radioisotope. Twenty Santa Ines sheep with seven months of age and averaging initial weight of 30.8 ± 6.41 kg were used and allocated to one of two treatments. Ten animals were orally infected (a single dose of 30,000 L3 larvae of T. colubriformis + 10,000 L3 larvae of H. contortus), and ten animals were not infected (control group). During the experimental, samples of blood, feces, urine, and diet refusals were collected and weighting were performed. A computed tomography was performed twice, before infection and at the end of the experiment, to evaluate changes in body composition. On 64-d after experimental infection, animals received an intravenous injection of 32P solution, and 7-d after they received radioisotope injection. The experimental animals were slaughtered, and tissue and bones were collected for P concentrations. The results showed that the parasitic infection compromised the absorption of P, impairing the metabolism, decreasing the mineral bioavailability increasing P bones reabsorption, and reducing bones density, also negatively compromising the infected animal performance.

Bioaccumulation and Depletion of the Antibiotic Sulfadiazine 14C in Lambari (Astyanax bimaculatus).

Antibiotics are present in the environment, primarily due to their release through wastewater treatment plants, agricultural practices, and improper disposal of unused medications. In the environment, these drugs can be bioaccumulated by organisms and transferred along the food chain. This is a problem when considering the consumption of fish meat. In the United States, legislation stipulates that the maximum residue limit for sulfadiazine (SDZ) should not exceed 100 µg kg-1. Lambari fishes have potential economic importance in aquaculture, as they are relatively easy to breed and can be raised in small-scale operations. Finally, studying the biology and ecology of lambari could provide valuable information about freshwater ecosystems and their inhabitants. The current work aimed to measure the bioaccumulation and depletion of the antibiotic SDZ 14C in lambari (Astyanax bimaculatus). For this purpose, the tests were divided into two stages; seven days of exposure and seven days of depletion, where one fish was randomly selected and sampled every day. In the exposure phase, the fish were fed the medicated feed three times a day at a concentration of 2.5 mg·g-1. The control fish were fed uncontaminated feed. For the depletion phase, the remaining lambari were transferred to clean tanks and fed uncontaminated feed three times a day. The fish samples were burned in the Oxidizer and the reading of radioactivity was performed in a liquid scintillation spectrometer. It is worth noting that on day 7 and day 14, the water in the aquariums was filtered through filter paper to collect the metabolic excrement. SDZ concentrations increased over the days and accumulation occurred in the fish, with day seven presenting the maximum accumulation value of 91.7 ng·g-1 due to feeding uptake. After the depletion phase on day 13, the value found was 0.83 ng·g-1. The bioconcentration factor calculated was 20 L·kg-1. After the bioaccumulation period, the concentrations of SDZ in the water and excreta were 4.5 µg·L-1 and 363.5 ng·g-1, respectively. In the depletion period, the concentrations in the water and excreta were 0.01 µg·L-1 and 5.96 ng·g-1, respectively. These results imply that there was little SDZ bioaccumulation in the fish, but that it was distributed in larger amounts in the water. This is due to the physicochemical properties of the molecule with the low Log P value. Regarding the maximum residue limit, the value was below the established value. This study contributes to understanding SDZ dynamics in an aquatic species native to Brazil.