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11.
In order to investigate the effects of benzoic acid on growth performance, nutrient digestibility, nitrogen balance and gastrointestinal microflora of piglets, we conducted a performance experiment and a separate balance study. The performance experiment involved four different dietary treatments: (1) basal diet (negative control); (2) basal diet supplemented with benzoic acid at 5 g/kg; (3) basal diet supplemented with benzoic acid at 10 g/kg; (4) basal diet supplemented with potassium diformate at 12 g/kg. Each dietary treatment was assigned to nine replicate groups, each consisting of two piglets. Live weight, daily weight gain, feed intake and feed conversion ratio were monitored as performance parameters over a 35-day period. Supplementation of the diet with benzoic acid resulted in a dose-dependent increase in feed intake and body weight gain and an improved feed conversion ratio. Piglets fed the diet supplemented with benzoic acid at 10 g/kg outperformed the control piglets in mean feed intake, body weight gain and feed conversion ratio by 9%, 15% and 6% respectively. Growth performance of the piglets fed the diet with benzoic acid at 10 g/kg was similar to that of piglets fed the diet supplemented with potassium diformate. In the balance experiment three groups of six piglets each were fed either a control diet or diets supplemented with benzoic acid at 5 or 10 g/kg respectively. Benzoic acid did not significantly affect nutrient digestibility but increased nitrogen retention. Piglets fed the diets supplemented with benzoic acid at 5 or 10 g/kg retained 5% and 6% more nitrogen, respectively, than control piglets. Supplementation of benzoic acid did not influence the pH value or the concentration of ammonia in the gastrointestinal tract but reduced the number of bacteria in the digesta. In the stomach the number of total aerobic, total anaerobic, lactic acid forming and gram-negative bacteria was reduced; in the duodenum the presence of benzoic acid reduced the number of gram-negative bacteria and in the ileum the number of total aerobic bacteria in a dose-dependent manner. Benzoic acid also considerably reduced the concentration of acetic acid in the duodenum. In conclusion, the data of this study suggest that benzoic acid exerts strong antimicrobial effects in the gastrointestinal tract of piglets and therefore enhances growth performance and nitrogen retention. 相似文献
12.
A 24-week performance trial was conducted to evaluate the efficacy of an experimental phytase on performance, egg quality, tibia ash content and phosphorus excretion in laying hens fed on either a maize- or a barley-based diet. At the end of the trial, an ileal absorption assay was conducted in order to determine the influence of phytase supplementation on the apparent absorption of calcium and total phosphorus (P). Each experimental diet was formulated either as a positive control containing 3.2 g/kg non-phytate phosphorus (NPP), with the addition of dicalcium phosphate (DCP), or as a low P one, without DCP addition. Both low P diets (containing 1.3 or 1.1 g/kg NPP) were supplemented with microbial phytase at 0, 150, 300 and 450 U/kg. The birds were housed in cages, allocating two hens per cage as the experimental unit. Each of 10 dietary treatments was assigned to 16 replicates. Low dietary NPP (below 1.3 g/kg) was not able to support optimum performance of hens during the laying cycle (from 22 to 46 weeks of age), either in maize or barley diets. Rate of lay, daily egg mass output, feed consumption, tibia ash percentage and weight gain were reduced in hens fed low NPP diets. The adverse effects of a low P diet were more severe in hens on a maize diet than in those on a barley diet. Low dietary NPP reduced egg production, weight gain, feed consumption and tibia ash content and microbial phytase supplementation improved these parameters. Hens given low NPP diets supplemented with phytase performed as well as the hens on positive control diets containing 3.2 g/kg of NPP. A 49% reduction of excreta P content was achieved by feeding hens on low NPP diets supplemented with phytase, without compromising performance. Phytase addition to low NPP diets increased total phosphorus absorption at the ileal level, from 0.25 to 0.51 in the maize diet and from 0.34 to 0.58 in the barley diet. Phosphorus absorption increased linearly with increasing levels of dietary phytase. Mean phosphorus absorption was higher in barley diets than in maize diets (0.49 vs 0.39). 相似文献
13.
Two growth experiments were conducted to evaluate in broiler chicks the compatibility between lasalocid medication in the feed (at 90 or 125 ppm) and a long-term administration of chloramphenicol either via the feed (500 ppm) or via the drinking water (500 mg/liter).The simultaneous administration of lasalocid and chloramphenicol generally caused severe growth depression, decreased feed intake and impaired feed conversion. Several chicks showed evident symptoms of intoxication, such as ataxia, leg weakness and paralysis. The development and frequency of these symptoms were dependent on the dosage of lasalocid and on the duration of the simultaneous administration.Biochemical examinations (Experiment 2) revealed in the affected chicks significant changes in several parameters, in particular a markedly increased activity of creatine kinase and GOT in the plasma. It confirmed that the observed leg weakness and paralysis were caused by myodegeneration. 相似文献
14.
Adrian Broz Priya Verma Christopher Appel Jenn Yost Craig Stubler Sean Hurley 《Compost science & utilization》2017,25(3):194-205
The use of vermicompost as a soil amendment is suggested as a method to reduce nitrogen (N) losses in crop production; however, it is unclear whether and how vermicompost can affect water quality after a significant irrigation or rainfall event. Bare-root strawberry plugs were grown in 1-gallon plastic pots. The treatments consisted of two media: (1) a peat:perlite soil-less mix and (2) a fine sand soil. Each media was amended with three levels of dairy manure vermicompost: 0, 10, and 25% by weight, and a biweekly synthetic fertilizer treatment of 150 mg N-P-K L?1 evaluated in a full factorial randomized block design. Drainage water from each plant was collected each week for 18 weeks and analyzed for NO3? concentration. In the first 2 weeks, high (1000–5000 mg L?1) amounts of NO3? leaching occurred in all vermicompost-amended media relative to non vermicompost-amended media, but this leaching significantly (p < 0.01) decreased over time across all vermicompost treatments. Strawberry growth response to 10% vermicompost was similar to synthetic fertilizer only treatments. Plants grown with vermicompost at 25% with synthetic fertilizer had the highest above-ground vegetative biomass (15.3 g) relative to plants with synthetic fertilizer only (5.3 g). These data suggest vermicompost addition rates of 10 and 25% by weight promote high vegetative biomass in greenhouse strawberry but may facilitate high initial nitrate leaching, which can negatively affect water quality and environmental health. 相似文献