Effect of disodium/calcium malate or supplementation on growth performance, carcass quality, ruminal fermentation products, and blood metabolites of heifers.

The aim of this study was to assess the effects of malate salts and culture on growth performance, carcass quality, ruminal fermentation products, and blood metabolites in heifers raised under southern Europe practical farm conditions. A total of 108 Charolaise cross heifers (214 ± 27.3 kg BW and 6.4 ± 1.1 mo of age) were housed in 18 pens of 6 animals each and used in a 114-d feedlot study. There was a totally randomized experimental design, and 6 pens were assigned to each of the following experimental diets: a control (no supplementation), the control plus 4 g of disodium/calcium malate mixture per kilogram of concentrate (2.12 g malate/kg), and the control plus 0.15 g of CBS 493.94 per kilogram of concentrate (1.5 × 10 cfu/kg). The control diet consisted of wheat-barley-based pelleted concentrate (32% starch, DM basis) and full-length barley straw. Concentrate and straw were fed separately ad libitum (5% orts) in an 88:12 ratio. On Days 0, 56, and 114, ruminal fluid and blood samples were obtained from each heifer between 2 and 2.5 h after the morning feeding by ruminocentesis and tail venipuncture, respectively. Body weight, concentrate ADFI, and G:F were recorded at 28, 56, 84, and 114 d. At slaughter, hot carcass weight and yield and carcass classification were determined in 2 representative heifers per pen (12 animals per dietary treatment). Supplementation with malate salts or did not affect concentrate ADFI ( = 0.98), ADG ( = 0.74), or G:F ( = 0.50) at any time during the experiment. At slaughter, there were no differences in carcass weight ( = 0.86), classification ( = 0.18), or carcass yield ( = 0.84) among experimental groups. Also, there were no differences treatments on ruminal pH ( = 0.24), ruminal fermentation products ( = 0.69, = 0.88, and = 0.93 for total VFA, NH-N, and lactate, respectively), and blood metabolites ( = 0.96, = 0.82, and = 0.15 for glucose, urea N, and lactate, respectively). In conclusion, under the feeding and management conditions of this study, diet supplementation with malate salts or did not have any significant effects on growth performance, carcass quality, ruminal fermentation products, and blood metabolites.

Efficacy of feed additives against Campylobacter in live broilers during the entire rearing period: Part B.

A total of 636 day-of-hatch Ross 308 broilers chicks were used in 4 independent trials carried out to screen the effect of 12 feed additives on reducing cecal colonization of Campylobacterin broilers. The tested additives were probiotics based on B. subtilis and S. cerevisae, a garlic extract, a blend of herbal substances and essential oils, two different combinations of essential oils and organic acids (OA), two mixtures of flavoring compounds, medium chain fatty acids (MCFA), monoglycerides (MG) of MCFA and MG-MCFA+OA. At 14 days of age, all the birds were orally infected with 0.1 mL of a bacterial suspension of C. jejuni ST-45 diluted at 10(5) cfu/mL in tryptone salt broth. In each trial, there was a positive control group and 2 (Trials 1 and 2) or 4 (Trials 3 and 4) additional treatment groups supplemented with additives, which were added to feed or water only to the finisher (21 to 42 d) diet (Trials 1 and 2) or to the starter (0 to 21 d) and finisher diets (Trials 3 and 4). Feed and water were available ad libitum. On days 35 and 42 of age in Trials 1 and 2, and on days 21, 35 and 42 of age in Trials 3 and 4, 10 (Trials 1 and 2) or 12 birds (Trials 3 and 4) per group were euthanized for cecal sampling. In Trial 1, birds fed with MCFA and MG-MCFA had a significant (P<0.05) reduction in cecal Campylobacter colonization compared to control at 35 d, but only the group treated with MG-MCFA maintained the reduction at 42 d. In Trials 2 to 4, no significant differences (P>0.05) in cecal Campylobacter counts were found between the treated and control animals. In conclusion, although none of the treatments were able to completely prevent the colonization of chickens with C. jejuni, MCFA and MG-MCFAs could reduce the pathogen counts when supplemented from 21 days onwards.

Efficacy of feed additives against Campylobacter in live broilers during the entire rearing period.

Poultry meat is the major source of human campylobacteriosis, the most frequently reported zoonosis in the EU. The prevalence of Campylobacter colonization in European broiler flocks is 71%. Despite considerable efforts, there is still no effective strategy available to prevent or reduce Campylobacter colonization in broilers. This study tested a wide variety of feed additives to reduce Campylobacter shedding in primary poultry production. Twelve additives containing organic or fatty acids, monoglycerides, plant extracts, prebiotics, or probiotics were tested. For each additive, broilers contaminated with Campylobacter jejuni were fed with an additive free diet (control group) or with a supplemented diet (treated group) and Campylobacter loads compared at three sampling times. No treatment was able to prevent broiler colonization by Campylobacter, and there was a high degree of variation in contamination among the birds. At 14 d of age, eight treatments significantly decreased the colonization level compared to the control group by a maximum of 2 log10 CFU/g. At 35 d of age, three of these treatments still had a significant effect with a maximum reduction of 1.88 log10 CFU/g for a probiotic. At 42 d of age, only one short-chain fatty acid was still significantly efficient with a mean reduction over 2 log10 CFU/g. In addition, a probiotic and a prebiotic-like compound significantly decreased the contamination by a maximum of 3 log10 CFU/g, only at the 42-d sampling period. This study gives promising results regarding the use of feed additives to reduce Campylobacter infection in flocks. Nevertheless, a global approach, combining intervention measures at the different steps of the broiler meat production chain could have a greater impact on the reduction of public health risk.

Feeding regimen and enzyme supplementation to rye-based diets for broilers.

A trial was conducted to study the influence of feeding regimen [ad libitum, (AL) vs. feed restriction, (FR)] and supplementation of the diet with a combination of xylanase and beta-glucanase on physiological parameters and performance of broilers fed rye-based diets. There were 4 dietary treatments arranged factorially with 2 feeding regimens (0 vs. 30% FR from 4 to 14 d), 2 enzyme doses (0 vs. 500 ppm), and an additional corn control diet. Each treatment was replicated 9 times from 4 to 25 d (15 chicks caged together) and 6 times from 25 to 46 d. From 4 to 46 d of age, FR did not affect weight gain and improved feed conversion of broilers (P < 0.05). Also, FR reduced the incidence of leg disorders, digesta viscosity, and pasted vents (P < 0.01) and increased relative weight of gizzard (P < 0.001). Enzyme supplementation (ES) improved average daily gain and feed conversion at all ages (P < 0.01), and the beneficial effects were greater for AL than for FR birds (P < 0.10). Also, ES reduced digesta viscosity (P < 0.001), relative weights of gizzard (P < 0.05) and crop (P < 0.01), and jejunum length (P < 0.05). Compared with feeding corn, feeding rye AL with or without ES impaired growth and feed conversion from 4 to 46 d (P < 0.01) and increased incidence of leg disorders (P < 0.05), viscosity of jejunum content (P < 0.01), and jejunum length (P < 0.05). We concluded that rye in feed impaired broiler performance and increased digesta viscosity and incidence of leg disorders and that FR and ES reduced the magnitude of the problem. The beneficial effects of ES on bird performance were more evident when birds were fed AL.

Alpha-amylase supplementation of broiler diets based on corn.

A 42-d trial was conducted to study the influence of exogenous alpha-amylase on digestive and performance traits in broilers fed a corn-soybean meal diet. There were two treatments (control and alpha-amylase supplemented diet) and six replicates (14 Cobb male chicks caged together) per treatment. At 7 d of age, alpha-amylase supplementation improved daily gain by 9.4% (P < or = 0.05) and feed conversion by 4.2% (P < or = 0.01). At the end of the trial, birds fed the alpha-amylase-supplemented diet ate more and grew faster (P < or = 0.05) and hadbetter feed conversion (P < or = 0.10) than broilers fed the control diet. Also, alpha-amylase supplementation improved apparent fecal digestibility of organic matter and starch (P < or = 0.01) and AMEn of the diet (P < or = 0.001). However, no effects were detected for CP or fat digestibility. Nutrient digestibility and AMEn of the diet increased with age (P < or = 0.001); however, no interactions of alpha-amylase x age were observed for any trait. Coefficients of apparent ileal and fecal digestibility of starch at 28 d of age were similar, which indicated that most of the undigested starch was not fermented in the hindgut of the chick. alpha-Amylase supplementation reduced relative pancreas weight (P < or = 0.001) but did not affect the weight of the remaining organs. Age consistently reduced intestinal viscosity and relative weights of all the organs (P < or = 0.001). The data indicated that alpha-amylase supplementation of a corn-soybean meal diet improved digestibility of nutrients and performance of broilers.

Influence of enzymes on performance and digestive parameters of broilers fed rye-based diets.

An experiment was conducted to study the influence of enzyme supplementation (ES) to rye-based diets on rate of food passage through the digestive tract, viscosity of jejunum content, volatile fatty acid concentration in ceca, and performance of broilers. There were seven treatments; six diets arranged factorially with three varieties of rye (Petkus, Prima, and Saratov V) and two levels of ES (0 or 500 ppm of an enzyme complex containing 858 IU of beta-glucanase and 864 IU of xylanase/g) and an additional control diet based on corn. Each treatment was replicated seven times (12 chicks caged together), and the trial lasted 25 d. Rye feeding increased intestinal viscosity and impaired bird performance at 25 d (P < 0.001). Among rye diets the greatest feed intake and weight gain were obtained with Petkus variety, which also produced the lowest intestinal viscosity. Enzyme addition reduced the time needed to recover 1% (0.78 vs. 0.98 h; P < 0.05) and 50% (4.2 vs. 6.5 h; P < 0.01) of the marker in feces and reduced the mean retention time of marker in the gastrointestinal tract (17.1 vs. 18.8 h; P < 0.05). Also, ES reduced intestinal viscosity (P < 0.001) and improved feed intake, daily gain, and feed conversion of birds from 4 to 25 d (P < 0.01) but did not modify volatile fatty acid concentration in ceca. We concluded that ES added to rye diets decreased intestinal viscosity and accelerated digestive transit, improving productive performance of broilers.