The Effects of Phytochemical Tannin-Containing Diets on Animal Performance and Internal Parasite Control in Meat Goats

ABSTRACT The Effects of Phytochemical Tannin-Containing Diets on Animal Performance and Internal Parasite Control in Meat Goats By Chassity Wright Haemonchus contortus (H. contortus) resistance has been reported against almost all chemical anthelmintics available for its control. H. contortus has a remarkable ability to develop resistance and threatens the viability of the goat industry in many regions of the world. Consequently, there is an urgent need to understand the genetic mechanisms underlying anthelmintic resistance and to discover new alternative methods of chemical and non-chemical control. With chemical anthemintics failing, this has led to the evaluation of plants as a natural source of anthemintic. Researchers are evaluating the effectiveness of phytochemical compounds, called tannins. Condensed tannins (CT) and hydrolyzable tannins (HT) exist, but HT is metabolized to toxic by-products. Therefore, CT are more widely used for research. The objective of this study was to compare the effects of CT containing diets of sericea lespedeza pellets (SLP), pine bark powder (PB), and a combination of SLP and PB on animal growth, fecal egg counts (FEC), packed cell volume using FAMACHA score, adult worm numbers, carcass characteristics, and blood serum chemistry in meat goats experimentally infected with 5,000 drug resistant H. contortus L3 larvae 6 weeks before the initiation of the study. Twenty-four Kiko-cross intact male goat yearlings (Capra hircus; BW = 38.6 ± 2.7 kg) were randomly assigned to four experimental treatments: 1) 30% bermudagrass hay (BG), 2) 30% PB, 3) 30% SLP, and 4) 15% SLP + 15% PB. Each treatment diet was completed with 70% commercial sweet feed and alfalfa pellets. Each of the ingredients for all experimental diets were individually measured out, mixed together by hand and distributed accordingly for 42 days. Starting on day zero of the study, animals were fed once a day and monitored for a 42-day performance period. Body weights, FAMACHA, and fecal samples were taken on day 0 and every 2 weeks until day 42. Blood samples were collected only on day 0 and day 42. At the end of the experiment the animals were sent to Fort Valley State University for carcass evaluation and adult worm counts from the abmomasum were conducted at Louisiana State University. The results showed that CT containing diets have no significant effects on final BW (P = 0.16) and ADG (P = 0.19). FEC results indicated that there was no significance among the CT treatments (P = 0.64) up to day 28. However, FEC in the mix diet was significantly reduced by day 42 (P = 0.05) compared to other treatment groups. There was interaction significance shown with day (P = 0.00), but no significance with treatment interaction and treatment per day interaction (P = 0.08). Carcass data indicated no significant differences in fasting weight (P = 0.24), hot carcass weight (P = 0.35), and dressing percentage (P = 0.83). Adult worm counts was lowest in the mixed diet (P = 0.02) compared to all other treatments (P \u3c 0.03 – 0.01). FAMACHA data was significant on day 21 (P = 0.05), lowest in the PB diet, and on day 42 (P = 0.05), lowest in both the SLP and mix diet. In the blood serum chemistry, all values were within the normal range for goats, suggesting that no liver damage occurred. This was confirmed by postmortem necropsy and dissection of the liver and kidney in this study (data not presented), which indicated no anatomical lesions on liver and kidney organs