Diet selection and trade-offs between condensed tannins and nutrients in parasitized sheep

Understanding Animal-Plant-Parasite Interactions to Improve the Management of Gastrointestinal Nematodes in Grazing Ruminants

Grazing systems have great potential to promote animal welfare by allowing animals to express natural behaviours, but they also present risks to the animals. Diseases caused by gastrointestinal nematodes are some of the most important causes of poor ruminant health and welfare in grazing systems and cause important economic losses. Reduced growth, health, reproduction and fitness, and negative affective states that indicate suffering are some of the negative effects on welfare in animals infected by gastrointestinal nematode parasitism. Conventional forms of control are based on anthelmintics, but their growing inefficiency due to resistance to many drugs, their potential for contamination of soil and products, and negative public opinion indicate an urgency to seek alternatives. We can learn to deal with these challenges by observing biological aspects of the parasite and the host’s behaviour to develop managements that have a multidimensional view that vary in time and space. Improving animal welfare in the context of the parasitic challenge in grazing systems should be seen as a priority to ensure the sustainability of livestock production. Among the measures to control gastrointestinal nematodes and increase animal welfare in grazing systems are the management and decontamination of pastures, offering multispecies pastures, and grazing strategies such as co-grazing with other species that have different grazing behaviours, rotational grazing with short grazing periods, and improved nutrition. Genetic selection to improve herd or flock parasite resistance to gastrointestinal nematode infection may also be incorporated into a holistic control plan, aiming at a substantial reduction in the use of anthelmintics and endectocides to make grazing systems more sustainable.

The effect of plant bioactive compounds on lamb performance, intake, gastrointestinal parasite burdens, and lipid peroxidation in muscle

Plant extracts have been widely used in animal production systems due to the benefits promoted by their bioactive components, mainly through their antioxidant effects and positive effects on animal growth, health, and meat quality. We determined whether bioactive compounds (BC) from grape (Vitis vinifera), olive (Olea europaea), and pomegranate (Punica granatum) have beneficial effects on lamb growth while controlling gastrointestinal parasitism and reducing skeletal lipid peroxidation in muscle. Fourteen lambs (4 to 5 mo of age) were housed in individual pens and assigned to two treatment groups (seven animals/group), where they received: 1) a basal diet of beet pulp:soybean meal (90:10) (CONTROL) and 2) the same diet, but containing 0.3% of BC extracted from grape, olive, and pomegranate (BNP). After 21 d of consuming their respective rations (period 1), all lambs were dosed with 10,000 L3 stage larvae of Haemonchus contortus. Intake, production, and physiological parameters were determined before infection (period 1), after oral dosage with L3 (period 2), and during early (period 3) and later (period 4) developmental stages of infection. Groups of animals did not differ in their ration intake or average daily gain, either before or after the infection, or in their parasitic burdens estimated through fecal egg counts (P > 0.05). Lambs under BNP showed greater feed efficiency before infection (P < 0.001), but the pattern reversed after infection. In addition, the inclusion of plant bioactives to the diet did not have an effect (P > 0.05) on blood or lipid peroxidation in muscle or on hemogram, serum concentration of haptoglobin, and immunoglobulin E. These results could be explained by low dietary doses and constrained absorption or ruminal inactivation of these compounds. Changes in feed efficiencies suggest a negative interaction between BC in the diet and parasitism, which warrants further research.

Effect of Artemisia absinthium and Malva sylvestris on Antioxidant Parameters and Abomasal Histopathology in Lambs Experimentally Infected with Haemonchus contortus

This study evaluated the effect of Artemisia absinthium and Malva sylvestris on antioxidant response and histopathological changes in the abomasa of the Haemonchus contortus infected lambs. Twenty-four lambs were divided into four groups: unsupplemented lambs (UNS), lambs supplemented with A. absinthium (ART), lambs supplemented with M. sylvestris (MAL), and lambs supplemented with both plants (ARTMAL). Lambs were infected orally with approximately 5000 third-stage (L3) larvae of H. contortus. The experiment was conducted for 75 d (days), all animals were then slaughtered; and the abomasal tissues were examined for antioxidant parameters and histopathology. The concentration of malondialdehyde in the abomasal mucosa was lower in ARTMAL (p < 0.05), and the total antioxidant capacity was higher in MAL (p < 0.05), than in UNS. Increased mucus production was observed in the ARTMAL. The number of mast cells in UNS and ART was significantly higher than the number in MAL (p < 0.01 and p < 0.05). Plasma cell numbers were higher in ARTMAL than the number in MAL (p < 0.05). Abomasal tissue regenerated more frequently in ARTMAL. These results represent the first report of the impact of A. absinthium and M. sylvestris on antioxidant parameters and local immune responses of abomasal mucosa of lambs infected with a GIN parasite.