Subtherapeutic antibiotic use in ruminant feeding to optimize rumen fermentation may lead to residues in meat and milk (6), as well as an increase in the inhibition of ruminal bacterial populations (7). For this reason, in 2006, the European Union banned the use of antibiotics as growth promoters in livestock feeding due to potential toxicities to host animals, potential rumen microbial adaptation, and risk of the presence of residues of these compounds in milk and meat, with potential effects on human health (8). ; In the present study, sensitive and mutant colonies of some ruminal bacterial species isolated from sheep, cattle, and buffalo were detected. We counted and considered "mutant colonies" the bacterial colonies grown in the clear inhibition zone in the Kirby–Bauer disk diffusion susceptibility test. Detected mutant colonies were higher in buffalo than in cattle and sheep. Duricef and metronidazole caused no mutations in any species. The others formed mutant colonies, where roxithromycin = polymyxin = chloramphenicol = gentamicin streptomycin = piperacillin > erythromycin > vancomycin = cefoperazone = cefotaxime > roxithromycin > polymyxin > chloramphenicol). The number of sensitive isolates of the different ruminant species for all the antibiotics was highest in buffalo, followed by cattle and then sheep (P < 0.05). We could conclude that subtherapeutic antibiotic use in ruminant feeding may lead to the formation of antibiotic-resistant mutant colonies, making their subtherapeutic effect nonexistent.
Feed cost represents about 60–70 % of rabbit keeping costs; therefore, maximizing utilization of nutrients is essential for the profitability and sustainability of rabbit production. Consequently, it has become very necessary to look for locally available, cheap, and nutritionally safe feed additives that would help to cut down production costs and improve production efficiency. Since the European Union banned most of the antibiotic growth promoters in animal nutrition due to cross and multiple resistances, much research has been conducted to explore the use of multi-enzymes as effective substitutes. ; The aim of this study was to evaluate the fertility status, milk output, mortality, and body thermoregulation of rabbit does as affected by different levels of multi-enzyme extracts (EZ) in their diets. A total of 120 Hy-Plus rabbit does were divided into four comparable experimental groups (n = 30 does per group). Animals of each group were divided in six pens (five animals per pen), and each pen was used as an experimental unit. The first group was kept untreated and fed a commercial diet alone without enzyme extracts (EZ0), while the other groups were fed the same diet but supplemented with 1 (EZ1), 3 (EZ3), and 5 (EZ5) kg/ton of enzyme extracts, respectively. Feeding EZ additive increased (P < 0.05) conception and kindling rates, litter size and weight at birth, and litter size and bunny weight at weaning, with decreasing (P < 0.05) abortion rate. Moreover, total milk yield increased (P < 0.05) with increasing level of enzyme supplementation. Pre-weaning mortality decreased (P < 0.05) with EZ inclusion. Signs of vitality (rectal temperature, skin temperature, earlobe temperature, respiration rate, and pulse rate) were improved with EZ inclusion. For all results, 5 kg EZ/ton of feed was more effective than 1 and 3 kg EZ/ton feed. It can be concluded that supplementation of EZ in rabbit diet decreased mortality rate and enhanced fertility status and milk output.
Subtherapeutic antibiotic use in ruminant feeding to optimize rumen fermentation may lead to residues in meat and milk (6), as well as an increase in the inhibition of ruminal bacterial populations (7). For this reason, in 2006, the European Union banned the use of antibiotics as growth promoters in livestock feeding due to potential toxicities to host animals, potential rumen microbial adaptation, and risk of the presence of residues of these compounds in milk and meat, with potential effects on human health (8). ; In the present study, sensitive and mutant colonies of some ruminal bacterial species isolated from sheep, cattle, and buffalo were detected. We counted and considered "mutant colonies" the bacterial colonies grown in the clear inhibition zone in the Kirby–Bauer disk diffusion susceptibility test. Detected mutant colonies were higher in buffalo than in cattle and sheep. Duricef and metronidazole caused no mutations in any species. The others formed mutant colonies, where roxithromycin = polymyxin = chloramphenicol = gentamicin streptomycin = piperacillin > erythromycin > vancomycin = cefoperazone = cefotaxime > roxithromycin > polymyxin > chloramphenicol). The number of sensitive isolates of the different ruminant species for all the antibiotics was highest in buffalo, followed by cattle and then sheep (P < 0.05). We could conclude that subtherapeutic antibiotic use in ruminant feeding may lead to the formation of antibiotic-resistant mutant colonies, making their subtherapeutic effect nonexistent.
Feed cost represents about 60–70 % of rabbit keeping costs; therefore, maximizing utilization of nutrients is essential for the profitability and sustainability of rabbit production. Consequently, it has become very necessary to look for locally available, cheap, and nutritionally safe feed additives that would help to cut down production costs and improve production efficiency. Since the European Union banned most of the antibiotic growth promoters in animal nutrition due to cross and multiple resistances, much research has been conducted to explore the use of multi-enzymes as effective substitutes. ; The aim of this study was to evaluate the fertility status, milk output, mortality, and body thermoregulation of rabbit does as affected by different levels of multi-enzyme extracts (EZ) in their diets. A total of 120 Hy-Plus rabbit does were divided into four comparable experimental groups (n = 30 does per group). Animals of each group were divided in six pens (five animals per pen), and each pen was used as an experimental unit. The first group was kept untreated and fed a commercial diet alone without enzyme extracts (EZ0), while the other groups were fed the same diet but supplemented with 1 (EZ1), 3 (EZ3), and 5 (EZ5) kg/ton of enzyme extracts, respectively. Feeding EZ additive increased (P < 0.05) conception and kindling rates, litter size and weight at birth, and litter size and bunny weight at weaning, with decreasing (P < 0.05) abortion rate. Moreover, total milk yield increased (P < 0.05) with increasing level of enzyme supplementation. Pre-weaning mortality decreased (P < 0.05) with EZ inclusion. Signs of vitality (rectal temperature, skin temperature, earlobe temperature, respiration rate, and pulse rate) were improved with EZ inclusion. For all results, 5 kg EZ/ton of feed was more effective than 1 and 3 kg EZ/ton feed. It can be concluded that supplementation of EZ in rabbit diet decreased mortality rate and enhanced fertility status and milk output.
Ruminal fermentation is accompanied by losses of the energy and protein consumed by dairy cows (Tamminga, 1992; Busquet et al., 2006) which may limit productive performance and contribute to release of pollutants to the environment (Calsamiglia et al., 2007). Ionophores have been used to reduce these losses (McGuffey et al., 2001), but the use of antibiotics in animal feeds has been banned in the European Union since January 2006 (Jiménez-Peralta et al., 2012) due to potential appearance of residues in milk (Russell and Houlihan, 2003). For this reason, there is substantial interest in evaluating the potential of using natural antimicrobials, such as plant extracts generally recognized as safe for human consumption (Busquet et al., 2006; Fandiño et al., 2008), to modify rumen microbial fermentation. Extract of Salix babylonica (SB) have been evaluated for their anti-microbial effects and for their potential to modulate ruminal fermentation and improve nutrient utilization in ruminants (Mejía-Hernández et al., 2013; Salem, 2012; Salem et al., 2010, 2011).The antimicrobial activity of SB extracts has been attributed to a number of plant secondary metabolites (PSM) such as alkaloids, saponins and phenolics (Jiménez-Peralta et al., 2011). Rumen microorganisms have the ability to degrade low concentrations of PSM without negative effects on rumen fermentation. Rumen microorganisms can also degrade alkaloids (Lanigan, 1970; Wachenheim et al., 1992), saponins (Lu and Jorgensen, 1987; Hu et al., 2005; Hart et al., 2008) and phenolics (Varel and Jung, 1986; Varel et al., 1991) and utilize them as an energy source. Some PSM can enhance protein metabolism and decrease methane production (Benchaar et al., 2007), and have the ability to suppress or stimulate microbial growth, increase binding of ammonia during urea ammoniation of straw and reduce odours from cattle manure in dairy barns (Makkar et al., 1998; Salem et al., 2012). In addition, some PSM reduce nutritional stress such as bloat and/or improve animal health and productivity (Patra et al., 2006; Benchaar et al., 2007, Xhomfulana et al., 2009; Salem et al., 2010). Positive effects on daily gain, voluntary feed intake and milk production (Salem et al., 2011) have been demonstrated, as well as a protective effect on dietary protein in the rumen in order to promote duodenal absorption, minimize excretion of nitrogen, modify the acetate to propionate ratio in rumen fluid and decrease the parasitic load (Salem et al., 2010; Jiménez- Peralta et al., 2011). Use of plant extracts could be limited by their secondary compound concentrations as consumption of large amounts of tannins or saponins may have a direct haemolytic effect and may even cause death (Athanasiadou and Kyriazakis, 2004). Moreover, long term feeding of plants rich in secondary compounds may have detrimental effects on animal health (Mahgoub et al., 2008). This experiment was conducted to determine effects of SB extract mixed in the diet on milk production and composition in Brown Swiss cows in addition to in vitro gas production of the diet fed to the cows with different doses of SB. ; A 3×3 Latin Square design was used to evaluate effects of 0, 150 and 300 mL of Salix babylonica (SB) extract mixed into the diet on daily milk production and composition in cows. Three Brown Swiss dairy cows (420±30.3 kg body weight), at late lactation (220±25.1 d in milk), were fed a diet with a restricted amount of concentrate and oat hay ad libitum twice daily in equal amounts. The SB extract was mixed daily with a small amount of concentrate and fed to the cows. In vitro gas production of the diet fed to the cows was recorded at 2, 4, 6, 8, 10, 12, 24, 48, and 72 h of incubation with 0, 0.6, 1.2 and 1.8 mL SB/g DM.
Unlike most of you, I hope, I have spent quite a lot of time in jail. This is not because I am a criminal, even though those who jailed me have called me a terrorist and worse. It is because I am a campaigner for democracy. I believe everyone has a right to vote and to be represented by a government they choose as free citizens. For that I have spent many years behind bars.
