Effect of commercial tannins on parasitic infection and immunity of lambs naturally infected with Haemonchus contortus.

This study aimed to evaluate the effects of different doses of quebracho extract tannins (Schinopsis lorenzii) (EQ) included in the basal diet (DB) on the count of eggs per gram of feces (EPG), count of parasites in the abomasum, hematological, and immunological parameters in lambs naturally infected with Haemonchus contortus. Forty-eight lambs were evaluated for 42 days and divided into four groups (n = 12): CONT- lambs that received DB without EQ supplementation; G1%- DB with EQ at 1% of dry matter intake (DMI) level; G3%- DB with EQ at the 3% of DMI level; G6%- DB with EQ at the 6% DMI level. For EPG counts, feces were collected weekly. For counting abomasal parasites, at the end of the experiment (D42) half of the lambs in each group were slaughtered. For hematological and immunological analysis, venous blood samples were collected at D0, D21, and D42 to perform the erythrocyte count, mean cell volume (MCV), hematocrit, differential leukocyte count, total plasma protein dosage, and serum IgA class anti-H. contortus using an indirect enzyme immunoassay (ELISA). In the EPG count, there was no significant difference (p > 0.05) between the groups compared with the control. Analysis of the abomasal parasite count showed Haemonchus contortus in its entirety; however, there was no significant difference (p > 0.05) in the number of males, females, and total parasites. No differences (p > 0.05) were observed in erythrocyte count, MCV, hematocrit, and total plasma protein. The average total leukocyte, monocyte, eosinophil, and basophil counts showed no difference (p > 0.05). However, the averages of segmented neutrophils in the G1% and G3% groups presented a reduction in the percentage of cells (p < 0.05) between D21 and D42. Regarding the lymphocyte count, a difference was observed in the CONT and G3% groups at D21 and D42 (p < 0.05), when compared to D0. The analyses of the average absorbance of anti-Haemonchus contortus serum IgA showed no difference (p > 0.05), when the groups were analyzed over time or when compared between them. It can be concluded that the inclusion of different doses of tannins from EQ did not alter the parasitological, hematological, and immunological parameters of lambs infected with H. contortus.

Intake and performance of growing lambs supplemented with quebracho tannins.

Tannins can modulate rumen fermentation and increase the bypass protein; however, the use of different doses and sources of condensed tannins (CT) in animal diets has divergent results. The aim of this study was to evaluate the effect of different levels of dietary quebracho extract inclusion, as a CT source, in the performance and carcass characteristics of growing lambs. Forty-eight weaned lambs (Texel, Suffolk, and Hampshire Down crossbred) were homogenously blocked into four groups and supplemented at 0, 10, 30, and 60 g tannins/kg dry matter intake (DMI) (CONT, T1%, T3%, and T6%, respectively). The DMI, the roughage to concentrate ratio, the feed conversion rate (FCR), the average daily gain (ADG), and the body condition score (BCS) were evaluated. After the trial, animals were slaughtered, and the cold carcass weight, carcass yield, and subcutaneous fat thickness (SFT) were determined. Higher levels of CT in T3% and T6% reduced (P < 0.001) the total DMI and intake of concentrate without impacting (P = 0.071) the roughage intake (% body weight). ADG was the lowest for T6%, although the total weight gain and BCS were the lowest also for T3% (P < 0.001). FCR was worst for T6% (P < 0.001). Regarding carcass characteristics, T6% had the lowest weight of carcass (P = 0.003) and SFT (P = 0.021) compared to CONT. Carcass yields were similar among all the groups (P = 0.247). T1% did not differ from CONT to any parameter (P > 0.05). Supplementing quebracho CT at a low dose did not show beneficial effects; moreover, higher doses of CT led to detrimental effects in intake and animal performance.

Salivary, serum, and abomasal mucus IgA as an immune correlate of protection against Haemonchus contortus infection in naturally infected lambs.

This study aimed to evaluate salivary, serum, and abomasal mucus IgA levels in lambs naturally infected with Haemonchus contortus. Thirty-seven crossbred lambs (½ Texel or ½ Ile de France) with an average age of 193 days were evaluated for 56 days after grazing on a contaminated pasture. Fecal samples were collected every 7 days to evaluate the EPG. Blood and saliva samples were collected for IgA measurement every 14 days. On D56, 29 animals were killed for parasite counting and IgA quantification in the abomasal mucus. Salivary, serum, and abomasal mucus IgA were measured by ELISA using third-stage larvae antigens. Salivary and mucus IgA were not correlated, but D14 salivary IgA correlated with EPG on D28 (r = -0.37) and D56 (r = -0.36); D28 salivary IgA correlated with D49 (r = -0.40) and D56 EPG (r = -0.44). Abomasal mucus IgA negatively correlated with EPG from D28 to D56 (r varied from _0.51 to -0.62) and with the counts of all parasitic stages (-0.60 to -0.67). The lambs were classified as susceptible (S) or resistant (R) according to EPG (D56 EPG and cumulative EPG) or IgA (salivary, serum, and mucus IgA). Based on D56 EPG and cumulative EPG, resistant lambs had higher D14 salivary IgA, mucus IgA, and total worm counts. For evaluations based on IgA levels, the EPG of S and R animals differed, indicating that IgA was an immune correlate of protection against natural infection with Haemonchus sp., mainly in the saliva sample of D14.

Implication of the fecal egg count reduction test (FECRT) in sheep for better use of available drugs.

The aim here is to present data on the efficacy of anthelmintics in sheep flocks in Rio de Janeiro, Brazil, and to discuss the interpretation of the fecal egg count reduction test (FECRT) for each nematode genus. Fecal eggs counts and pre- and post-treatment coprocultures were performed, the former to evaluate the efficacy of and the latter to determine the overall parasite prevalence. An additional efficacy test was performed at Farm # 1 a year after the initial test. Severe anthelmintic resistance was found for the flocks, with no FECRT sensitivity at any of the 22 farms evaluated. However, an analysis of the infective larvae showed that some drugs were effective against certain parasitic genera; i.e., levamisole was more effective against Haemonchus spp. and moxidectin against Trichostrongylus spp. In the additional FECRT performed at Farm # 1, moxidectin and nitroxynil were ineffective separately, but when applied in combination they were highly effective due to their efficacy against Haemonchus (nitroxynil) and Trichostrongylus (moxidectin), respectively. The use of the FECRT targeting the parasitic nematode species prevalent on farms may make it possible to choose more effective anthelmintics.

Implication of the fecal egg count reduction test (FECRT) in sheep for better use of available drugs / Implicação do teste de redução da contagem de ovos nas fezes (TRCOF) em ovinos para melhor uso dos anti-helmínticos disponíveis

Abstract The aim here is to present data on the efficacy of anthelmintics in sheep flocks in Rio de Janeiro, Brazil, and to discuss the interpretation of the fecal egg count reduction test (FECRT) for each nematode genus. Fecal eggs counts and pre- and post-treatment coprocultures were performed, the former to evaluate the efficacy of and the latter to determine the overall parasite prevalence. An additional efficacy test was performed at Farm # 1 a year after the initial test. Severe anthelmintic resistance was found for the flocks, with no FECRT sensitivity at any of the 22 farms evaluated. However, an analysis of the infective larvae showed that some drugs were effective against certain parasitic genera; i.e., levamisole was more effective against Haemonchus spp. and moxidectin against Trichostrongylus spp. In the additional FECRT performed at Farm # 1, moxidectin and nitroxynil were ineffective separately, but when applied in combination they were highly effective due to their efficacy against Haemonchus (nitroxynil) and Trichostrongylus (moxidectin), respectively. The use of the FECRT targeting the parasitic nematode species prevalent on farms may make it possible to choose more effective anthelmintics.

Resumo O objetivo deste trabalho foi apresentar dados sobre a eficácia de anti-helmínticos em rebanhos ovinos no Rio de Janeiro, Brasil, e discutir a interpretação do teste de redução da contagem de ovos nas fezes (TRCOF) para cada gênero de nematoide. A contagem de ovos fecais (OPG) e coprocultura pré e pós-tratamento foram realizadas para avaliar a eficácia e a prevalência geral do parasito, respectivamente. Um teste de eficácia adicional foi realizado na Fazenda # 1 após um ano do teste inicial. Resistência anti-helmíntica grave foi encontrada, não havendo sensibilidade no TRCOF em nenhuma das 22 fazendas avaliadas. No entanto, na análise das larvas infectantes observou-se que algumas drogas foram eficazes contra certos gêneros parasitários; por exemplo, o levamisol foi mais eficaz contra Haemonchus spp. e a moxidectina contra Trichostrongylus spp. No TRCOF adicional realizado na Fazenda 1, a moxidectina e o nitroxinil foram ineficazes separadamente, mas quando aplicados em combinação, foram altamente eficazes devido à sua eficácia contra Haemonchus spp. (nitroxinil) e Trichostrongylus spp. (moxidectina), respectivamente. O TRCOF visando às espécies de nematoides parasitas prevalentes nas fazendas pode possibilitar a escolha de anti-helmínticos mais eficazes.

Overview of anthelmintic resistance of gastrointestinal nematodes of small ruminants in Brazil.

Frequent and inappropriate use of all classes of antiparasitic drugs in small ruminants has led to failures in their effectiveness, culminating in a global problem of anthelmintic resistance. Brazil stands out as one of the world's leaders in publications about anthelmintic resistance, and for having the most numerous reports of this resistance in small ruminants in the Americas. These studies have involved mainly the fecal egg count reduction test (FECRT) and its correlation with field management practices. In vivoeffectiveness testing is conducted in areas where livestock is of greater economic significance, e.g., in the South (sheep) and Northeast (goats), or is important for research and economic centers, such as the Southeast (sheep). The most widely studied species is sheep, for which the widest range of drugs is also evaluated. Despite significant advances achieved in molecular research, laboratory analyses should include knowledge about the reality in the field so that they can become feasible for the producer. Moreover, molecular studies can be underpinned by the analysis of field studies, such as the maintenance of antiparasitic effectiveness over time and the mechanisms involved in this process.

Overview of anthelmintic resistance of gastrointestinal nematodes of small ruminants in Brazil / Panorama da resistência anti-helmíntica em nematoides gastrointestinais de pequenos ruminantes no Brasil

Abstract Frequent and inappropriate use of all classes of antiparasitic drugs in small ruminants has led to failures in their effectiveness, culminating in a global problem of anthelmintic resistance. Brazil stands out as one of the world’s leaders in publications about anthelmintic resistance, and for having the most numerous reports of this resistance in small ruminants in the Americas. These studies have involved mainly the fecal egg count reduction test (FECRT) and its correlation with field management practices. In vivoeffectiveness testing is conducted in areas where livestock is of greater economic significance, e.g., in the South (sheep) and Northeast (goats), or is important for research and economic centers, such as the Southeast (sheep). The most widely studied species is sheep, for which the widest range of drugs is also evaluated. Despite significant advances achieved in molecular research, laboratory analyses should include knowledge about the reality in the field so that they can become feasible for the producer. Moreover, molecular studies can be underpinned by the analysis of field studies, such as the maintenance of antiparasitic effectiveness over time and the mechanisms involved in this process.

Resumo O uso frequente e inapropriado de todas as classes de antiparasitários em pequenos ruminantes levou a falhas de eficácia, culminando na problemática global de resistência anti-helmíntica. O Brasil destaca-se como sendo um dos pioneiros nas publicações com resistência anti-helmíntica no mundo e por ter o maior número de relatos em pequenos ruminantes na América. Essas pesquisas envolvem principalmente o teste da redução da contagem de ovos nas fezes (TRCOF) e sua correlação com as práticas de manejo utilizadas no campo. Os estudos de testes de eficácia in vivo localizam-se em áreas onde há maior importância dos rebanhos como nas Regiões Sul (ovinos) e Nordeste (caprinos), ou com importância em polos de pesquisa e econômicos, como a região Sudeste (ovinos). Ovina é a espécie mais estudada e com maior gama de drogas avaliadas. Mesmo com grande avanço em pesquisas moleculares, as análises laboratoriais devem envolver o conhecimento da realidade do campo para que possam se tornar viáveis ao produtor. Além disso, a análise dos estudos de campo pode nortear estudos moleculares como, por exemplo, a manutenção da eficácia das drogas ao longo dos anos e os mecanismos envolvidos em tal processo.

Composição tecidual e perfil de ácidos graxos do lombo de cordeiros terminados em pasto com níveis de suplementação concentrada / Tissue composition and fatty acids profile of lambs loin finishing on pasture with concentrate supplementation

A composição tecidual da carne é característica importante na avaliação da qualidade sensorial e nutricional do produto. O presente trabalho avaliou a composição tecidual e o perfil de ácidos graxos do lombo de cordeiros desmamados aos 42 dias de idade média e terminados em pasto de azevém com níveis diários de suplementação concentrada (0, 1 e 2 por cento do PV e ad libitum). O delineamento experimental foi de blocos ao acaso com três repetições. Os cordeiros foram abatidos ao atingirem 32kg de peso vivo. O lombo direito foi utilizado para determinação da composição tecidual e o esquerdo para análise de perfil de ácidos graxos. As análises de variância e de regressão foram realizadas com auxílio do programa SAS (2001). A suplementação concentrada de cordeiros terminados em pasto não teve efeito (P>0,05) sobre o desenvolvimento muscular e ósseo; no entanto, promoveu acréscimo linear na deposição de gordura intermuscular e total. Os níveis de suplementação estudados não tiveram efeito (P>0,05) sobre a quantidade e o percentual de cada ácido graxo da carne dos cordeiros. A suplementação concentrada de cordeiros desmamados em pasto de azevém aumentou a deposição de gordura na carcaça sem afetar a qualidade da carne para o consumo humano, considerando-se o perfil de ácidos graxos.

Meat composition is an important aspect on evaluation of sensory and nutritional quality of the product. This work had the objective of evaluating tissue composition and fatty acids profile of loin lambs weaned at 42 days of mean age and finished on ryegrass pasture with levels (0 percent; 1 percent and 2 percent of BW; ad libitum) of daily concentrate supplementation. The experiment was allocated in randomized blocks design with three replications. Lambs were slaughtered when individual live weight reached 32kg. Tissue composition was determined in right loin and left loin was used for fatty acids profile analyses. Analysis of variance and regression were performed by using SAS (2001). The concentrate supplementation of lambs finished on pasture did not affect (P>0.05) muscle and bone development, however, promoted linear increase on intermuscular and total fat. Levels of supplementation did not affect (P>0.05) the amount and percentage of each fatty acids in lambs meat. The concentrate supplementation of weaned lambs finished on ryegrass pastures increased fat covering on carcass without changing meat quality to human feeding considering fatty acids profile.