Coccidiostatic effects of tannin-rich diets in rabbit production.

The potential anti-eimerial effect of tannin containing resources such as sainfoin and carob in rabbits was tested on does at pre-weaning and to growing rabbits in their feed. The trial began at parturition (D0), when 24 does and their litters were assigned into three groups. They were fed either with a control (Group CO), a carob (containing 10% carob pods meal) (Group CP) or a sainfoin diet (containing 34% dehydrated sainfoin pellets) (Group SA). All diets were made isoproteic and isoenergetic and also balanced for crude fibre but differed by their tannin content. Weaning occurred at D37, and growing rabbits remained in the same cage until D51. Then, they were transferred to fattening cages until the end of the trial (D104) and slaughtering. Weight gain of young rabbits among the three groups (mean = 31.2 g/day) did not differ statistically. The mortality rates were 10% (SA), 15% (CP) and 20% (CO), respectively, but the differences were not statistically significant. Post-weaning economical feed conversion ratio (FCR) was reduced between rabbits of group SA compared to CO and CP groups. Faecal oocyst count (FOC) in group SA was 60% lower than in CO and CP groups. Areas under the curve (AUCs) calculated between sampling days and FOC, after transfer to fattening cages, was 62% lower in group SA than in CO and CP groups. The main Eimeria species identified (from D59 to D83) was Eimeria magna (53% of oocysts). AUCs for E. magna did not differ according to diet. In conclusion, the diet containing sainfoin reduced oocyst excretion of Eimeria spp. by 60%, and improved the economical FCR.

Anthelmintic activity of some Mediterranean browse plants against parasitic nematodes.

The anthelmintic properties of tannin-rich plants are being explored as an alternative to chemical drugs. Most data have been acquired on legume forages, but only few on browse plants. The present study aimed to (i) screen the in vitro effects of extracts from 7 Mediterranean plants on Haemonchus contortus, (ii) verify the role of tannins using an inhibitor, polyvinyl polypyrrolidone (PVPP) and (iii) verify the in vivo effects of extracts from 4 plants. Significant inhibition was shown in vitro using a larval migration inhibition (LMI) assay for all extracts except that from Olea europaea var. koroneiki. After adding PVPP, the LMI values were restored to control levels for all plants except Pistacia lentiscus and Ceratonia siliqua, confirming a role for tannins in the activity. In the in vivo experiment, 48 lambs composed 6 groups, depending on diet. On Day 0, groups G1-G5 received H. contortus and Trichostrongylus colubriformis larvae and G6 remained uninfected. The various diets were distributed from Days 14 to 45: P. lentiscus (G1), Quercus coccifera (G2), C. siliqua (G3), Onobrychis viciifolia (G4), or Medicago sativa for the 2 control groups (G5, G6). Egg excretion, packed cell volumes (PCVs) and inorganic phosphate were measured weekly throughout the entire experimental period. At slaughter, the worms were enumerated and their fecundity assessed. Consumption of the 4 browser plants did not provoke differences in pathophysiological measurements but there were significant decreases in egg excretion, mainly explained by significant decreases in worm fecundity for both species, without any statistical difference in worm numbers.