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Resin acids extracted from coniferous trees are known for their antimicrobial and antifungal effects. This trial investigated the effect of a natural resin acid-enriched composition (RAC) on the gastrointestinal microbiota and productive performance of broiler chicken. The results demonstrated that at or above 5 mg/l, RAC prevented the growth of a pure culture of Clostridium perfringens, a causative agent of necrotic enteritis in poultry. Next, the effects of RAC on the microbial community were studied in a fermentation model with both the microbial inoculum and substrate for the microbes isolated from the ileum of broiler chickens. RAC was included at 0, 0.1 and 1 g/kg digesta, and supplementation decreased the relative proportion of lactic acid and increased that of acetic acid produced during the fermentation in a dose-dependent manner. At 1 g/kg inclusion, RAC decreased the density of lactobacilli. The final part of the experiment investigated the influence of RAC on the performance and intestinal microbiota of necrotic enteritis (NE)-challenged broiler chickens. A wheat and soy -based diet was supplemented with RAC at 0, 0.5, 1 and 3 g/kg. The chickens were challenged with Eimeria maxima oocysts on day 11, and a pure culture of C. perfringens on day 14. On day 17, the final day of the trial, RAC inclusion at 1 and 3 g/kg of feed significantly increased body weight. At 3 g/kg RAC numerically decreased the daily mortality seen during the challenge period. In the ileum, RAC at 1 g/kg reduced the NE-associated peak of microbial lactic acid production. Overall, the data suggested that the dietary ingredient RAC has the potential to act as a performance-enhancer and microbial modulator in broiler chickens.
Exogenous enzymes are commonly added to poultry diets to improve nutrient utilisation, reduce excretion of nutrients into the environment as well as to improve zootechnical performance and reduce the cost of production. A series of four experiments were conducted in broilers to determine the efficacy and tolerance to an enzyme product (Vegpro™) containing protease and xylanase activities in wheat-soybean meal (SBM) diets fed to broilers from 1 to 39 or 42 d of age. Collectively, four experiments tested the following exogenous protease activity levels in wheat-SBM diet at levels of 0, 2,500, 5,000, 10,000, 20,000, 30,000, 40,000 or 100,000 HUT/kg of feed. Analysis of the four experiments together confirmed that Vegpro™ improved average daily gain and feed conversion ratio, especially in birds up to 21 d of age. Overall, inclusion of Vegpro™ to broiler diets at 10,000 HUT protease per kg of feed was shown to provide the maximum performance benefit (i.e. weight gain and feed conversion ratio). An exceptionally high protease activity (100,000 HUT/kg, ten times the manufacturer's recommended inclusion rate) was well tolerated and did not adversely affect the measured health and performance indicators from 1 to 42 d of age.
Nutrient deposition in eggs is largely dictated by the dietary composition of laying hen feed, particularly in terms of specific fatty acids and antioxidants. In the present study, the nutritional quality of a range of commercially available egg varieties, marketed as omega-3 enriched; corn-fed; free range and standard caged, were assessed by determining fatty acid profiles and antioxidant status. Across each egg variety, significant differences were observed in key fatty acids such as palmitic, oleic, linoleic, alpha-linolenic and docosahexaenoic acid (DHA) (P ≤ 0.05). Egg yolks enriched with a stated dietary source of omega-3 fatty acid DHA were shown to have significantly improved levels of DHA (P ≤ 0.05), approximately 4.5-fold higher than standard caged eggs. Compared with free range, corn fed and caged, eggs from diets enriched with a source of omega-3 were shown to have considerably altered omega-6: omega-3 ratios, amounting to 1.5–2.1 fold reductions. Yolk antioxidant activity was improved for omega-3 enriched eggs, particularly in hexane fractionated samples. The inclusion of omega-3 fatty acids to the diet resulted in eggs with improved DHA contents and antioxidant status, highlighting the importance of poultry diet composition for egg nutritional quality.
A 4 × 2 factorial experiment was conducted to investigate the effect of a processed soy protein (PSP) on broiler performance and digestive physiology. Four inclusion levels of PSP (0, 25, 50 or 100 g/kg in either corn or wheat-based diets) were used in the starter diets. Feed intake was significantly lower (P < 0.01) on corn-based diets than those on wheat-based diets at 35 d. Over the first 10 d, chicks on corn-based diets tended (P < 0.09) to have higher body weight (BW) than wheat-based diet chicks. Across the 35 d trial, PSP level showed a strong tendency (P < 0.06) to be related to higher BW in birds, regardless of grain type. Both grain and PSP experimental factors significantly (P < 0.01, and P < 0.001) interacted at an early age, improving BW and feed conversion ratio (FCR) for birds received high PSP on wheat-based diets. Significantly heavier (P < 0.01) small intestine and gizzard + proventriculas weights at an early age, and heavier (P < 0.001) gizzard + proventriculas and pancreas during the grower stage were recorded in birds fed the corn-based diets. At 24 d, pancreatic chymotrypsin amidase and lipase enzymes were significantly (P < 0.01) more active in chickens fed the wheat-based diet. The interaction of PSP level and the type of the grain was significant (P < 0.01) for pancreatic chymotrypsin amidase and lipase as well as jejunal maltase (P < 0.05). Both experimental factors had a significant influence on jejunum histomorphology at 24 d of age (P < 0.001). There was a significant interaction between level of PSP and the type of grain (P < 0.05) resulting in the highest villus surface areas being seen for birds fed the corn-based diet and receiving the medium level of PSP. The trial demonstrated that PSP supplement can be included at between 50 and 100 g/kg of starter diets, depending on the basal diet.
The nutrient availability in animal feeds can be improved by including exogenous enzymes to the feed, either by helping breakdown anti-nutritional factors or by increasing digestibility of complex ingredients thereby releasing more nutrients for utilisation. This process can improve the efficiency of meat and egg production, increase animal health, decrease feeding costs and reduce nutrients in animal waste. Proteases are protein-digesting enzymes that are used in animal nutrition to break down storage proteins in various plant materials and proteinaceous anti-nutrients in vegetable proteins. The analysis of exogenous proteases in feed additives and after they have been added to feed has proven technically challenging. Accordingly, the purpose of this work was to validate a method for the determination of the activity of protease in animal feed additives and supplemented animal feed. The approach used for the assay was to adapt an assay based on the hydrolysis of haemoglobin. The method validations examined a range of parameters including; linearity & range; uncertainty, sensitivity, accuracy and studies designed to highlight any possible matrix effects on various types of supplemented feed. The assay method described herein is convenient and inexpensive and could be applied to the analysis of proteases in animal feeds during quality control and in investigating fraudulent adulteration of feed to ensure the authenticity and traceability of the product.
The appearance of a red hue to the hair in black coated cats and dogs has previously been reported as a “red hair syndrome”. Such changes in hair colour are related to an alteration in the proportions of two types of pigments produced by melanocytes; black eumelanin and brown pheomelanin. In black cats, it has been demonstrated that higher levels of phenylalanine + tyrosine (Phe+Tyr) than those recommended for growth are required to support eumelanin synthesis. The purpose of this study was to evaluate if a similar observation could be made in dogs. Twelve black coated puppies (Black Labrador retrievers and Newfoundlands) were divided into 3 groups of 4 and fed 3 diets with increasing concentrations of Phe+Tyr (A: 4 g/Mcal; B: 5.8 g/Mcal; C: 7 g/Mcal) for a period of 6 months. Quantification of plasma amino acids (Phe, Tyr, Cys) and spectrocolourimetry of hair samples from the Labrador retrievers (as the a* dimension of CIE Lab system) were performed at the beginning, during and at the end of the study. There was a significant negative linear relationship between plasma Tyr levels and a* values of hair in Labrador dogs on diets A and B, suggesting that a diet with total Phe+Tyr content of 6 g/Mcal (higher than the growth recommended allowance) was necessary to ensure an optimal black coat colour in these puppies and that levels up to 7 g/Mcal can lead to a more intense black coat colour. Moreover, similar to what was found in kittens, plasma levels of Tyr up to 54 μmol/l did not guarantee an optimal black colour coat and led to the “reddish hair” appearance in black coated puppies.
The aim of this study was to compare the effects of feeding two diets with different macronutrient proportions (high protein, low carbohydrate and low protein, high carbohydrate) on the digestibility and post-prandial endocrine responses of cats fed at maintenance levels, and to evaluate the effectiveness of the marginal ear vein prick technique for the measurement of blood glucose levels in feline studies. Two diets were fed to 16 adult domestic short-haired cats for a period of three weeks (eight cats per diet). Following a seven-day dietary adaptation period, the apparent macronutrient digestibility of the two diets was determined (days 8-19) using the total faecal collection method. The faeces were freeze dried, ground and analysed for dry matter, crude protein, crude fat and gross energy and then apparent digestibility was calculated. On days 20 and 21, the post-prandial glucose responses of the cats fed a single meal of one of the two diets were measured in serial blood samples collected using the marginal ear vein prick technique.
Results showed that the high protein, low carbohydrate diet had higher (p < 0.05) apparent digestibility of dry matter, crude protein, crude fat and energy, lower (p < 0.01) daily faecal output and smaller fluctuations in blood glucose concentrations. Despite the two groups of cats having similar calorific intakes, the cats fed the high protein diet lost weight over the study period, whereas those fed the high carbohydrate, low protein diet gained weight. The marginal ear vein prick technique proved to be an effective alternative to catheterisation for blood glucose determination. The high protein diet tested in the current study, in addition to being more aligned to the cat's natural carnivorous diet, may be beneficial for weight management and blood glucose control in cats.
Mannan-oligosaccharides (MOS), as zootechnical feed ingredients, are widely used in animal nutrition. MOS has been commercially available since the launch of Bio-Mos® in the early 1990's and has a substantial body of scientific papers and practical examples of its efficacy. Since 1999, the use of MOS in animal feed has become more prominent, mainly due to the European ban on prophylactic antibiotic growth promoters in animal feed. MOS, with its ability to bind and limit the colonisation of gut pathogens, has proven to be an effective solution for antibiotic-free diets, as well as providing support for immunity and digestion. MOS has been shown to improve gastrointestinal health, thus improving wellbeing, energy levels and performance. Most MOS products, particularly those that have been scientifically developed, derive from the cell wall of the yeast, Saccharomyces cerevisiae. In 2009, a mannose-rich fraction (MRF) product was commercially launched as a ‘second generation’ of these MOS-type products, with enhanced activities in immune modulation and intestinal health. The purpose of this paper is to review the existing data on the benefits of MOS for all species of animals, discuss its mechanisms of action in vivo and compare the benefits of using second generation MRF to original MOS.
Feline degenerative joint disease causes pain and disability and therefore represents a welfare concern for captive animals. Alternatives to traditional pharmaceutical therapies are gaining popularity and this study aimed to evaluate the efficacy of an egg-shell membrane therapy in captive cheetahs and leopards. Seven animals were treated with SteadfastTM and monitored for radiographic changes (n = 6) and lameness score (n = 7) over a 42 day period. A reduction in lameness was determined over the course of the study (p = 0.01), and improved orthopaedic status detected in 50% (3/6) of animals via radiographic examination. Surprisingly, a negative dose response was detected, whereby animals receiving lower doses exhibited the most marked changes in lameness score. Despite the small sample size and subjective scoring of lameness, this preliminary study demonstrates the need for further investigation into the use of an eggshell membrane-based supplement to improve mobility in captive felids with degenerative joint disease.
The following trial was conducted to evaluate the impact of feeding Yea-Sacc® (YS; Alltech Inc, USA), a zootechnical feed additive based on a live probiotic strain of Saccharomyces cerevisiae, to lactating dairy cows over a 12 week period. Sixty-four primiparous and multiparous Holstein dairy cows, grouped to give similar range of parity, physiological and milk production stages, were selected for the study. Cows were equally allocated to either a control feed group or a diet supplemented with YS (32 cows per treatment). The test diet was formulated to include YS (Yea-Sacc® Farm Pak) incorporated in the total mixed ration (TMR), supplying a target dose of 5 × 107 CFU/kg feed dry matter (DM). This target dose delivered 1 × 109 CFU/cow/day, for a cow consuming 20 kg feed (DM basis) daily. Each cow was considered a replicate unit. Cows were fed a nutritionally adequate total TMR plus hay and a supplementary protein/energy concentrate (calculated according to milk yield) for 12 weeks, supplied once a day after the morning milking. Weigh backs of feed were recorded daily, with refusals being maintained at 3% of the total intake. During the 12 week study period, YS had significant beneficial effects on milk production (+0.8 kg/day; P = 0.003), energy corrected milk production (+1.4 kg/day; P < 0.0001), synthesis of milk protein (+36 g/day; P = 0.001), milk protein content (+0.3 g/kg; P = 0.009), and milk urea content (−0.09 mg/l; P = 0.004). The synthesis of milk fat was similar between treatments but milk fat content was lower for the YS group compared to the control group (−1.1 g/kg; P = 0.0002). Lactose content was always higher (+0.8 g/kg; P < 0.0001) for the YS group, indicating enhanced energy utilisation. In general, the effect of YS was higher during the first study period (one to seven weeks), when cows were in early lactation and the production potential was higher. YS cows produced significantly more milk during the study, and an additional 220 kg milk per cow was sold from this group from the output measured from the beginning of the study to two weeks post-trial. However, the statistical analysis including the post-study period did not show a significant effect. The 305-day simulated milk production was higher for the YS group (+400 kg/cow) but again the difference was not significant. In conclusion, YS at a target dose of 5 × 107 CFU/kg DM improved milk production and milk quality in healthy dairy cows. In addition, when the data were included in a whole-farm model, feeding YS reduced methane emissions by 4%, reduced the number of animals required for the desired milk production by 4% and increased overall farm margins by 1.4%.
Exogenous carbohydrases are commonly added to monogastric feed to help degrade non-starch polysaccharides (NSP). This action can increase the nutrient availability of feedingstuffs and decrease digestive disturbances, thus improving animal performance. This in turn can lead to improved feed conversion efficiency in meat and egg production. In light of the benefits associated with dietary xylanase inclusion, so too has it become increasingly relevant to quantity them in poultry feed premixtures with additional enzyme activities and directly in compound feed. Hitherto, the analysis of the activity of xylanase in animal feeds has proved difficult. Despite the widespread acceptance of the DNS method for the quantification of xylanase activity, it is not without limitations which can lead to erroneous under- or over-estimation of activity, and is particularly variable depending on the feed matrix wherein it is measured. The current method validation examined the following parameters: linearity, precision, uncertainty, sensitivity (limit of detection and limit of quantification) and the experiments were designed to highlight any interference from protease co-ingredients and possible matrix effects in various types of supplemented feed. The assay method described is convenient and inexpensive and could be applied to the rapid and routine analysis of xylanases in animal feeds during quality control and in investigating fraudulent adulteration of feed to ensure the authenticity and traceability of the product.
Seventy two, one day old Friesian heifer calves were fed whole milk either via regular or slow release teats on commercial calfeteria systems (Milkbar, McInnes Manufacturing Limited, Waipu, New Zealand) for 42 days. For the entire period, the consumption time for the calves fed on the regular flow rate teat calfeterias was twice as fast as for those fed using the slow teats. Meal intake was numerically higher for the calves fed milk using the slow teats. At day 42, calves on the slow teats had a strong trend towards higher daily gain. At 14 days of age, visual differences in curding were seen in the abomasum of culled calves, with the fast teat-fed animals having large lumps of curded milk surrounded by watery liquid, whereas the slow teat-fed calves had much smaller particle sized curding in thicker fluid. Lactose digestion in the stomach was significantly higher for the calves fed using the slow teats, and there was a strong trend for higher levels of free protein in the ileum. Using slow flow rate teats to feed calves from day old to weaning appears to have an important impact on digestive processes in the immature gut. Such improvements in digestion and rumen development in young calves may assist in the digestion of milk and other feeds, leading to improved growth performance. Under farm conditions, slow release teat systems may reduce scours and other digestive problems in young calves during peak milk intake (up to 15 d of age), due to increased ileal digestion of nutrients, preventing undigested nutrient flow to the hind gut. It may also reduce cross-sucking behaviour in calves, which is undesirable.