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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.

Two independent trials were carried out to evaluate the effect of feed form, whole wheat (WW) and oat hulls (OH) addition on gastrointestinal (GIT) weight and Campylobacter jejuni colonization in orally infected birds. In Trial 1, there were six treatments factorially arranged with two feed forms (mash vs pellets), and three levels of WW from 1-21/22-42d: 0/0, 7.5/15%, 15/30%. Broilers were allocated in cages (3 birds/cage, 12 cages/treatment). In Trial 2, there were three treatments: a mash diet, a mash diet including WW (7.5% from 1–21 and 15% from 22-42d), and a third treatment including also 5%OH. Broilers were allocated in floor pens (1 pen with 30 birds/treatment). At 14d, all broilers in Trial 1 or 3 broilers/pen in Trial 2 were orally challenged with 1.5 x 105 cfu of C. jejuni ST-45 /. In Trial 1, birds fed pelleted diets consumed 13.5% more feed, gained 31% more weight, and presented 12.9% better feed conversion for the whole trial (P<0.05). Pelleting decreased the relative weight of GIT and gizzard and increased the relative weight of proventriculus (P<0.05). Mash diets decreased pH in the gizzard (P<0.05). Inclusion of WW decreased the relative weight of proventriculus, increased gizzard weight, and reduced pH in the gizzard (P<0.05). At 21d of age, mash tended to reduce C. jejuni compared to pellets (7.85 vs 8.27 log10cfu/g; P = 0.091) and WW inclusion at 7.5/15% reduced C. jejuni colonization when compared to lower and higher inclusion (P<0.05). In Trial 2, birds fed T3 (WW+OH) showed 1.38 log10cfu/g less than birds fed Control diet (P<0.05). In conclusion, despite of the clear morphological changes in the GIT derived of FF and WW inclusion, no clear reductions in C. jejuni populations in the ceca were observed. However, WW and OH inclusion to mash diets significantly reduced cecal C. jejuni colonization at 42 days.

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SummaryA study was conducted to evaluate productive performance in laying hens fed diets with reduced nutrient density based on the nutritional contribution of a Buttiauxella phytase in laying-hen diets from 21-57 weeks of age. A commercial laying hen diet was offered ad libitum to the 480 ISA Brown laying hens from 18-21 weeks of age. From 21 weeks onwards, the hens received one of four dietary treatments: a positive control (PC) diet, a down specified diet (DS1) + phytase at 300 FTU/kg, a second downspecified diet (DS2) + phytase at 600 FTU/kg and a third test diet formulated as per DS1 + phytase at 1,200 FTU/kg feed. The PC was formulated based on ISA breeder recommendations. DS1 was formulated with reduction of 0.149% available P, 0.134% Ca, 55 kcal/kg AME, 0.33% CP, digestible amino acids (up to 0.015%) and 0.013% Na based on the contribution of Buttiauxella phytase at 300 FTU/kg. DS2 was formulated with reduction of 0.177% available P, 0.159% Ca, 60 kcal/kg AME, 0.61% CP, digestible amino acids (up to 0.028%) and 0.02% Na based on the contribution of Buttiauxella phytase at 600 FTU/kg. Every dietary treatment was fed to 12 cages containing 10 hens each. The trial treatments did not include a full, DS negative control, as ethical considerations regarding birds' welfare when feeding such diets over such an extended period of time did not permit this. No significant differences were seen in hen-day egg production, feed intake, egg weight, feed to egg mass ratio, shell, yolk or albumen proportion, unsaleable eggs or shell breaking strength in laying hens fed the PC diet or the DS diets with added phytase. Yolk colour increased significantly with phytase supplementation. Supplementing the DS1 diet with 300 FTU and the DS2 diet with 600 FTU resulted in non-significant differences in tibia ash, Ca and P, compared to the PC diet. The data from this study indicated that applying the nutrient contributions for Buttiauxella phytase at 300 and 600 FTU/kg maintained the egg production, BW and egg quality parameters compared to PC. The best economic efficiency value during the whole experimental period was recorded with phytase at 600 FTU/kg when full matrix values are used. When commercial diets are formulated based on ISA breeder recommendations, lowering diet nutrient density while supplementing with phytase reduced the overall diet cost, which should contribute to the profitability of egg production.