Leucine and methionine deficiency impairs immunity to gastrointestinal parasites during lactation

Abstract

Lactating rats reinfected with Nippostrongylus brasiliensis fed low-crude protein (CP) foods show reduced lactational performance and less resistance to parasites compared with their high-CP counterparts. Here, we hypothesised that feeding high-CP foods deficient in specific essential amino acids (AA) would result in similar penalties. Second-parity lactating rats, immunised with 1600 N. brasiliensis infective larvae before mating, were fed foods with either 250 (high protein; HP) or 150 (low protein; LP) g CP/kg, or were HP deficient in either leucine (HP-Leu) or methionine (HP-Met). On day 1 of lactation, litter size was standardised at twelve pups. On day 2, dams were either reinfected with 1600 N. brasiliensis larvae or sham-infected with PBS. Dams and litters were weighed daily until either day 8 or 11, when worm burdens, and inflammatory cells and systemic levels of N. brasiliensis-specific Ig isotypes were assessed. Data from five out of sixteen HP-Met rats were omitted due to very high levels of food refusals from parturition onwards. Relative to feeding HP foods, feeding LP, HP-Met and HP-Leu foods reduced dam weight gain and, to a lesser extent, litter weight gain, and increased the number of worm eggs in the colon, indicative of a reduction in resistance to parasites. However, only feeding LP and HP-Leu foods resulted in increased worm numbers, while none of the feeding treatments affected systemic Ig, mast and goblet cells, and eosinophil numbers. The present results support the view that resistance to parasites during lactation may be sensitive to specific essential AA scarcity.

The effect of helminth infection on the microbial composition and structure of the caprine abomasal microbiome

“…2-oxoglutarate ferredoxin oxidoreductase [EC:1.2.7.3] belongs to a family of oxidoreductases that participate in the citric acid (TCA) cycle, suggesting the H. contortus -altered abundance of Prevotella affects energy metabolism in the caprine gut microbial ecosystem. During helminth infection in ruminants, feed intake is significantly reduced while endogenous protein loss accelerates due, in part, to the processes that enhance mucin excretion and the synthesis of effector molecules for host immune responses 29 30 . As a result, protein availability and quality in the intestine play a larger role as the infection progresses and serves as a main determinant of host nitrogen utilization efficiency 31 .…”

Physiological roles of tryptophan in teleosts: current knowledge and perspectives for future studies

“…Moreover, both innate and adaptive immune responses are dependent upon the adequate provision of amino acids for the synthesis of antigen‐presenting molecules, immunoglobulins and cytokines (Sakkas et al . ).…”

Dietary tryptophan and methionine as modulators of European seabass (Dicentrarchus labrax) immune status and inflammatory response

“…There is growing interest on the role of AA in immune functions of fish, since increasing evidence support that AA present important features in higher vertebrates as they regulate: (1) the activation of T-lymphocytes, B-lymphocytes, natural-killer cells and macrophages; (2) the cellular redox stage, gene expression and lymphocyte proliferation; and (3) the production of antibodies, cytokines and cytokines substances as NO and superoxide [49]. Both innate and adaptive immune responses are dependent upon adequate provision of AA for the synthesis of antigen-presenting molecules, immunoglobulins and cytokines [57].…”

“…Accordingly, an optimal balance among AA in the diet and circulation, is crucial for whole-body homeostasis [49]. At the same time, requirements for protein or AA may also increase as a direct consequence of metabolic changes associated with inflammation and infection [57]. However, few studies have been conducted to assess the effect of dietary AA levels on immune responses and disease [54].…”