Four Holstein steers with ruminal and duodenal cannulas were used in a 4 × 4 Latin square design to examine the effect of daily intake of 0, 2, 4 or 6 g/steer of standardized plant extract containing a mixture of quaternary benzophenanthridine alkaloids and protopine alkaloids (QBA+PA) on the characteristics of ruminal fermentation and characteristics of digestion. The basal diet consisted of a steam-flaked corn-based finishing diet that contained 62% corn and 12% sudangrass hay and the rest of diet was composed of mainly dried distillers grains, molasses, fat, and minerals. The source of QBA+PA used was Sangrovit-RS (Phytobiotics Futterzusatzstoffe GmbH, Eltville, Germany) and supplementation levels of 2, 4, and 6 g Sangrovit-RS∙steer∙d, which represented a net daily ingestion of approximately 6, 12, and 18 mg of QBA+PA compounds, respectively. Inclusion of QBA+PA linearly increased ( = 0.04) flow to the duodenum of nonammonia N and linearly decreased ( < 0.01) duodenal flows of ammonia N. Ruminal microbial efficiency (duodenal microbial N; g/kg OM fermented in the rumen) and protein efficiency (duodenal nonammonia N; g/g N intake) were increased ( < 0.05) as the level of QBA+PA increased. There were no effects of QBA+PA supplementation on ruminal, postruminal, and total tract digestion of OM, starch, and NDF, but postruminal and total tract digestion of N increased ( < 0.01) as the level of QBA+PA increased. Digestible energy of the diet tended to increase (linear affect, = 0.09) with QBA+PA supplementation. Ruminal pH and total VFA molar concentrations were not different between treatments. Ruminal NH-N concentration linearly decreased ( = 0.02) with QBA+PA supplementation. Ruminal molar proportion of acetate increased ( = 0.04) as the supplementation level of QBA+PA increased. It is concluded that QBA+PA supplementation enhances efficiency of N utilization in feedlot steers fed a steam-flaked corn-based finishing diet. This effect was due, in part, to enhanced ruminal microbial efficiency, decreased ruminal degradation of dietary nonammonia N, and enhanced postruminal N digestion.

Background Diets with increasing levels of energy were fed for 42 days to 200, 1-day old male broiler chickens to evaluate growth performance, carcass characteristics and chemical composition of meat. The study was performed in the subtropical area of northeastern Mexico. Treatments diets (T) for starter and finisher phases had apparent metabolizable energy (AME; kcal/kg) of: 2960 and 3040 (T1); 3000 and 3080 (T2); 3040 and 3120 (T3); 3080 and 3160 (T4), respectively. Within each of the growing phases the four treatment diets were formulated to contain similar levels of crude protein, amino acids, and other nutrients. In a completely randomized design, birds were allocated to the four treatments with five replicates (floor pens) of 10 birds each. The trial was divided in two phases (starter and finisher) of 21 days each (42 days total).ResultsWeight gain was not influenced by energy level; however, feed conversion efficiency was improved in the diets with 3040 and 3120 kcal/kg AME (T3; P < 0.05). There was no influence of treatment on total carcass weight or carcass cuts (P > 0.05). Meat from breast muscle had similar crude protein percentages among treatments; ether extract was higher in T1 than T4 (P < 0.05). The percentages of water, ether extract, ash and crude protein in thigh meat were not significantly different (P > 0.05) among treatments. ConclusionsFor this study carried out in a dry tropical area, the moderate increase in dietary energy concentration (diet with 3040 and 3120 kcal/kg AME, T3) enhanced feed conversion efficiency of broiler chickens.

In experiment 1, eighty crossbred steers (239±15 kg) were used in a 229-d experiment to evaluate the effects of increasing levels of enzymatically hydrolyzed yeast (EHY) cell wall in diets on growth performance feedlot cattle during periods of elevated ambient temperature. Treatments consisted of steam-flaked corn-based diets supplemented to provide 0, 1, 2, or 3 g EHY/hd/d. There were no effects on growth performance during the initial 139-d period. However, from d 139 to harvest, when 24-h temperature humidity index averaged 80, EHY increased dry matter intake (DMI) (linear effect, p<0.01) and average daily gain (ADG) (linear effect, p = 0.01). There were no treatment effects (p>0.10) on carcass characteristics. In experiment 2, four Holstein steers (292±5 kg) with cannulas in the rumen and proximal duodenum were used in a 4×4 Latin Square design experiment to evaluate treatments effects on characteristics of ruminal and total tract digestion in steers. There were no treatment effects (p>0.10) on ruminal pH, total volatile fatty acid, molar proportions of acetate, butyrate, or estimated methane production. Supplemental EHY decreased ruminal molar proportion of acetate (p = 0.08), increased molar proportion of propionate (p = 0.09), and decreased acetate:propionate molar ratio (p = 0.07) and estimated ruminal methane production (p = 0.09). It is concluded that supplemental EHY may enhance DMI and ADG of feedlot steers during periods of high ambient temperature. Supplemental EHY may also enhance ruminal fiber digestion and decrease ruminal acetate:propionate molar ratios in feedlot steers fed steam-flaked corn-based finishing diets.

Compared to controls, zilpaterol (ZH) supplementation did not affect dry matter intake (DMI), but increased carcass adjusted daily weight gain (ADG, 36.7%), gain efficiency (34.2%) and dietary net energy (26.0%), and decreased (23.4%) the ratio of observed:expected DMI. Compared to controls, supplemental ZH increased hot carcass weight (6.4%), dressing percentage (3.2%), LM area (15.6%), and shoulder muscle:fat ratio (28.7%), but decreased kidney-pelvic-heart fat, and fat thickness. Supplemental ZH increased 10.9 and 14.3% whole cut weight of loin and leg, respectively, and the proportion (as percentage of CCW) of leg (4.3%). These increases were reflected in greater forequarter and hindquarter weights. Lambs fed ZH increased (4.6%) empty body weight (EBW) and reduced (14.7%) liver/spleen weight (as g/kg EBW). Likewise, ZH supplementation tended (P=0.08) to lower (8.9%) visceral fat. Growth performance, energetic efficiency, hot carcass weight, dressing percentage, LM area and whole cuts were not different across supplemental ZH sources. However, compared with non-supplemented controls, only ZIL appreciably decreased carcass fat distribution, including fat thickness, percentage kidney pelvic and heart fat, shoulder fat, and visceral fat.

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