Nutritional deficiencies and parasitic disease: Lessons and advancements from rodent models

Dietary protein supplementation results in molecular and cellular changes related to T helper type 2 immunity in the lung and small intestine in lactating rats re-infected with Nippostrongylus brasiliensis

Acquired immunity to gastrointestinal nematodes reduces during late pregnancy and lactation which is known as periparturient relaxation of immunity (PPRI). Protein supplementation reduces the degree of PPRI in a rat model re-infected with Nippostrongylus brasiliensis, but the underlying molecular mechanisms have yet to be elucidated. Here, we hypothesized that protein supplementation will enhance T helper type 2 immunity (Th2) in the lung and small intestine. Nulliparous Sprague-Dawley rats were given a primary infection of N. brasiliensis prior to mating and restrictedly fed diets with either low protein (LP) or high protein (HP) during pregnancy and lactation. Dams were secondary infected with N. brasiliensis on day 2 post-parturition, and histology and gene expression were analysed for tissue samples collected at days 5, 8 and 11. Genes related to Th2 immunity in the lung, Retnla, Il13 and Mmp12, and in the intestine, Retnlb, were upregulated in HP dams compared to LP dams, which indicates the effect of dietary protein on Th2 immunity. HP dams also had increased splenic CD68+ macrophage populations compared to LP dams following secondary infection, suggesting enhanced immunity at a cellular level. Our data assist to define strategic utilization of nutrient supply in mammals undergoing reproductive and lactational efforts.

Endoparasite and nutritional status of Suffolk lambs in seven production systems

Lambs are the most susceptible category for parasite infections; therefore, the choice of the production system can influence nutritional status and reduce parasite infections. The present study aimed to evaluate the endoparasites and nutritional status of meat lambs in seven production systems. In the feedlot, they were (S1) early weaned lambs in feedlot and (S2) unweaned lambs in feedlot with controlled suckling. On pasture, they were (S3) early weaned lambs on pasture without supplementation, (S4) early weaned lambs on pasture with concentrate supplementation post-weaning, (S5) unweaned and unsupplemented lambs on pasture, (S6) unweaned lambs on pasture with concentrate supplementation and creep-feeding and (S7) unweaned lambs on pasture with free access to creep-grazing on white clover (Trifolium repens). Suffolk lambs (n = 132) were evaluated from 45 to 101 days of age, at 14-day intervals (0, 14, 28, 42 and 56 days). Parasite faecal egg count (FEC), FAMACHA score (FMC), average daily weight-gain and body condition score (BCS) were evaluated. The animals were treated with anthelmintics when they had FMC 3, 4 or 5 and/or FEC above 700. BCS and FEC (r = –0.361) and BCS and FMC variables (r = –0.313) were negatively correlated (P ≤ 0.01). FEC was lower in feedlot and in creep-feeding animals than in the other systems after the second evaluation (28 days). The weaned feedlot-lamb and controlled-suckling systems presented the best performance. On pasture, the animals in creep-feeding and creep-grazing had the best performance. Weaned and unsupplemented lambs on pasture had the lowest daily weight-gain (63 g/day) and the highest FMC scores (43% of animals) and the lowest BCS (mean 1.5). The endoparasite and nutritional statuses of the lambs were strongly correlated and were influenced by the production system, mainly when the ewes were present and the lambs received supplementation on pasture.

The 'Toolbox' of strategies for managing Haemonchus contortus in goats: What's in and what's out

A dynamic and innovative approach to managing the blood-consuming nematode Haemonchus contortus in goats is critical to crack dependence on veterinary anthelmintics. H. contortus management strategies have been the subject of intense research for decades, and must be selected to create a tailored, individualized program for goat farms. Through the selection and combination of strategies from the Toolbox, an effective management program for H. contortus can be designed according to the unique conditions of each particular farm. This Toolbox investigates strategies including vaccines, bioactive forages, pasture/grazing management, behavioural management, natural immunity, FAMACHA, Refugia and strategic drenching, mineral/vitamin supplementation, copper Oxide Wire Particles (COWPs), breeding and selection/selecting resistant and resilient individuals, biological control and anthelmintic drugs. Barbervax(®), the ground-breaking Haemonchus vaccine developed and currently commercially available on a pilot scale for sheep, is prime for trialling in goats and would be an invaluable inclusion to this Toolbox. The specialised behaviours of goats, specifically their preferences to browse a variety of plants and accompanying physiological adaptations to the consumption of secondary compounds contained in browse, have long been unappreciated and thus overlooked as a valuable, sustainable strategy for Haemonchus management. These strategies are discussed in this review as to their value for inclusion into the 'Toolbox' currently, and the future implications of ongoing research for goat producers. Combining and manipulating strategies such as browsing behaviour, pasture management, bioactive forages and identifying and treating individual animals for haemonchosis, in addition to continuous evaluation of strategy effectiveness, is conducted using a model farm scenario. Selecting strategies from the Toolbox, with regard to their current availability, feasibility, economical cost and potential ease of implementation depending on the systems of production and their complementary nature, is the future of managing H. contortus in farmed goats internationally and maintaining the remaining efficacy of veterinary anthelmintics.