avoparcin and Body-Weight

Groups of 90 male broilers each were administered the antibiotic avoparcine mixed into feed in concentrations of 7.5, 10, and 15 ppm and achieved a higher mean body weight than the controls fed without this admixture. At the end of the 70-d fattening period, histological examination was carried out on selected individuals. The small intestine, liver, bursa of Fabricius, thymus, thyroid gland, pancreas, kidneys, heart, and skeletal muscle were observed on paraffin sections stained with hematoxylin and eosin. Cell proliferation was assessed in the liver and small intestine by means of bromodeoxyuridine labeling. The exposure to avoparcine resulted in a decreased cell proliferation in both tissues when compared to controls. In addition, hypertrophy of the hepatocytes and development of reactive lymphoid tissue in the bursa of Fabricius, which occurred in the controls, were absent in the treated animals. These observations indicate that the growth-promoting effect of avoparcine is related to a restriction in the host animals of responses to intestinal bacteria. No adverse pathological changes were observed in the examined tissues, indicating that avoparcine was well tolerated.

Topics: Animals; Anti-Bacterial Agents; Body Weight; Bursa of Fabricius; Cell Division; Chickens; Glycopeptides; Intestines; Liver; Male; Time Factors

1. The aim of the experiment was to test the possible interactions of an enzyme complex and a food antibiotic on the growth and metabolism, carcase yield, whole body composition and nutrient deposition in broilers. The basal diet contained 400 g/kg barley. The four treatments were as follows: O--without supplements (control), E--enzyme complex Roxazyme G, 200 mg/kg, A--antibiotic avoparcin, 10 mg/kg, EA--Roxazyme G, 200 mg/kg plus avoparcin, 10 mg/kg. 2. Roxazyme G positively influenced weight gain, food conversion efficiency, energy metabolisability, fat and nitrogen utilisation and the dry matter content of droppings. Fat and energy deposition in the whole body were also increased, whereas protein deposition and carcase yield were not influenced. 3. Avoparcin increased energy metabolisability and fat utilisation, but had no influence on nitrogen utilisation. No significant improvements from avoparcin were seen in growth or in nutrient deposition in the body. The fibre degradability (NDF and ADF fraction) was significantly depressed by antibiotic supplementation. 4. The inclusion of both supplements to the diet did not have a fully additive effect on growth, energy metabolisability, or fat and nitrogen utilisation. The interaction between enzyme and antibiotic for food conversion efficiency during the first experimental period (7 to 21 d) was nearly significant (P = 0.053). Except for fibre degradability (P < or = 0.01), no other significant interactions between enzyme and antibiotic were found.

Topics: Animal Feed; Animals; Anti-Bacterial Agents; Body Composition; Body Weight; Chickens; Enzymes; Glycopeptides; Glycoside Hydrolases; Multienzyme Complexes; Weight Gain

The effect of growth-stimulating agents (15 ppm of virginiamycin, 10 ppm of avoparcin and 12 ppm of nitrovin) and that of seven days' treatment with 300 ppm of furazolidone on the performance of broilers was studied in an experimental study of 9,600 animals. Furazolidone was fed in either the fourth or the fifth week of life and combined with virginiamycin or nitrovin. Non-significant improvements in growth were observed when virginiamycin (1.5 per cent), avoparcin (0.7 per cent) and nitrovin (0.7 per cent) were administered. Treatment with furazolidone for seven days resulted in substantial retardation of growth. When broilers were treated during the fourth week of life, the retardation of growth was largely compensated for during the other two weeks. Treatment in the fifth week of life resulted in lower weights prior to slaughter. Therefore, care should be taken in recommending treatment with furazolidone at the end of the fattening period of broilers.

Topics: Animal Feed; Animals; Anti-Bacterial Agents; Body Weight; Chickens; Food Additives; Furazolidone; Glycopeptides; Growth Substances; Nitrovin; Virginiamycin

The anticoccidial drugs narasin, lasalocid, monensin and salinomycin, with and without avoparcin, were fed to 1280 broiler chickens from 1 to 49 d old. At day 49 significant interactions were detected between avoparcin and the anticoccidial compounds for body weight and food consumption. This indicated that the increases in body weight and food consumption obtained with avoparcin were greater with some anticoccidial compounds (lasalocid and salinomycin for body weights and lasalocid for food consumption) than with others (monensin and narasin for body weights and monensin, narasin and salinomycin for food consumption). Overall there was evidence that avoparcin increased body weight (5.8%), food consumption (2.5%) and efficiency of food utilisation (2.9%). In addition avoparcin produced significant increases in plucked weight and the proportion of visceral fat together with and decreases in the proportions of edible giblets and waste offal.

Topics: Animals; Anti-Bacterial Agents; Body Composition; Body Weight; Chickens; Coccidiostats; Eating; Glycopeptides

No evidence was found for an interaction between dietary crude protein content and the presence or absence of two proprietary food additives used as sources of avoparcin and zinc bacitracin. The food additives had a similar effect in increasing rate of growth resulting in significant improvements of about 2% in the food conversion ratios.

Topics: Animals; Anti-Bacterial Agents; Bacitracin; Body Weight; Chickens; Dietary Proteins; Drug Interactions; Eating; Female; Glycopeptides; Male

One-hundred and fifty crossbred yearling-heifers, averaging 264 +/- 17 kg were fed a 77% barley diet for 140 days to evaluate the effect of 0, 33, 49.5 and 66 ppm avoparcin and 33 ppm monensin on growth rate, feed efficiency, carcass quality and ruminal volatile fatty acid (VFA) concentration. Heifers were allotted by weight to 25 pens (six head per pen) in a randomized complete block design of five treatments and five replicates per treatment. On day 140, rumen fluid was obtained from a randomly selected replicate of six heifers from each treatment for VFA analysis. Carcass data and liver samples were obtained at slaughter on day 147. All avoparcin-fed cattle consumed less feed per unit gain (P less than .05) than did those in the control group. Feed intakes of the monensin-fed heifers and the heifers fed 49.5 ppm avoparcin were lower (P less than .05) than those of the control group. There were no differences (P greater than .05) between treatments for measured carcass, liver or rumen parameters.

Topics: Animals; Anti-Bacterial Agents; Body Weight; Cattle; Fatty Acids, Volatile; Female; Furans; Glycopeptides; Monensin