Use of whole wheat, along with compounded feeds, for poultry feeding is a common practice in many parts of the world. However, studies investigating the use of other grains are limited. In the present study, the influence of including whole maize, with differing hardness, in broiler diets on the performance, nutrient utilisation and digestive tract development was examined. The experimental design was a 3 × 2 factorial arrangement of treatments, evaluating maize hardness (hard, semi-hard or soft) with diets based on ground maize or 115 g/kg whole maize replacing ground maize. The three maize cultivars were ground in a hammer mill to pass through a 4 mm sieve and six diets were developed based on one of the three cultivars. Following mixing, all diets were cold pelleted through a 3 mm die. Each of the six diets was fed to six replicate cages (eight birds per cage) from day 1 to 21 post-hatch. Maize hardness and whole maize inclusion had no effect (P>0.05) on weight gain. Maize hardness influenced (P<0.05) feed intake and feed per gain, while these two parameters were unaffected (P>0.05) by the inclusion of whole maize. The apparent metabolisable energy (AME) was unaffected (P>0.05) by maize hardness and whole maize inclusion. Maize hardness increased the ileal digestibility of nitrogen (P<0.05) and starch (P=0.06). The relative weight of the gizzard was greater (P<0.05) in birds fed hard and semi-hard maize compared to soft maize, and was greater (P<0.05) when whole maize was included. These results indicated that 115 g/kg of ground maize can be replaced by whole maize in broiler starter diets with no adverse effects on growth performance and thus can reduce the cost of feed manufacture.

Phytase is applied in animal feed based on its standard activity measured at pH 5.5, however the relative activity at pH 3 (e.g. stomach pH, the main site for the breakdown of phytate) varies among the commercial phytases, ranging from 56% (an E coli phytase) to 235% (Buttiauxella phytase). These diverse sources of phytases have varying capability for degrading phytate and, correspondingly, different P, digestible amino acid and metabolisable energy matrix values. In addition, the matrix values recommended by different phytase suppliers are not comparable, as different methodologies have been used to determine them. Phosphorus (P) and other matrix values can be determined by direct measurement of digestible P (dP) improvements by the addition of phytase above a negative control in large numbers of in vivo studies using increasing phytase doses. Alternatively, matrix values can be assessed by indirect measurement, using inorganic P (usually mono- or dicalcium sources) as a reference, typically based on tibia or metacarpal ash as a response parameter to estimate available P equivalence, either at a single or different phytase doses. When using the indirect measurement, the available P equivalence with increasing phytase doses may be calculated based on a log linear model. Although both methods are acceptable methodologies, direct measurement may under-estimate and indirect measurement may over-estimate matrix values, and a large number of in vivo studies give the best estimates of matrix values. Phytase efficacy can be influenced by phytase source, dose level, dietary composition (Ca level and Ca: P ratio). Phytase end users are encouraged to be aware of the methods used by suppliers to determine matrix values, before applying them in their feed formulations.

This study evaluated the effect of Bacillus subtilis C-3102 (Calsporin®) addition to the diet on faecal characteristics and nutrient digestibility in healthy adult dogs. Sixteen Beagles received either a low-energy control diet (CON; 3.35 Mcal metabolisable energy (ME)/kg with 21.8, 27.9, and 50.3% ME as protein, fat, and nitrogen-free extractives (NFE), respectively) or the same diet supplemented with Bacillus subtilis at 1 × 109 CFU/kg diet as probiotic (PRO) for four weeks in a parallel design (eight dogs per diet). In the prior two weeks, all dogs received a high-energy diet (Advance Medium Adult, Affinity Petcare®, 3.81 Mcal ME/kg ME with 24.8, 41.2, and 34% ME protein, fat, and NFE, respectively). Faecal consistency, dry matter (DM), pH, and NH3 were analysed on fresh samples collected at the start and weekly throughout the study. Additional samples were collected for the determination of lactate and short-chain fatty acids (SCFA) on days 0 and 21. In week four, a five–day total faecal collection was conducted in six dogs from each diet for the determination of nutrient apparent digestibility. Dogs fed the PRO diet had more firm faeces (P = 0.011) than control dogs and a higher faecal DM content in the first two weeks (P < 0.05). Feeding the PRO diet resulted in a decline in NH3 over four weeks (P = 0.05) and in faecal pH in the first two weeks (P < 0.05) alongside an increase in SCFA content (P = 0.044), mainly acetate (P = 0.024). Faecal lactate did not differ between diets (P > 0.10). Dogs fed the PRO diet showed a higher apparent digestibility of fat (P = 0.031) and NFE (P = 0.038) compared to control dogs. Dog food supplementation with Calsporin® at 1 × 109 CFU/kg improved faecal quality, enhanced fat and carbohydrate digestibility, and contributed to the gut health of dogs by reducing gut ammonia and increasing SCFA content.

A study was conducted to investigate the effect of method of whole wheat inclusion on performance and caecal microbiota profile of broiler chickens. Fluorescence in situ hybridisation analysis was used to characterise the microbiota by using genus-specific probes. Three treatments, namely, ground wheat (GW) or 200 g/kg whole wheat (WW) replacing GW before or after pelleting were evaluated. A total of 144, one-day-old male broilers (Ross 308) were allocated to 18 cages (eight broilers per cage) based on body weight and six cages were randomly assigned to each treatment. The diets were offered ad libitum from day 11 to 35 post-hatch. The WW fed birds, regardless of the method of inclusion, resulted in poorer weight gain (P < 0.05) and reduced feed intake (P < 0.001), but a similar feed per gain (P > 0.05) compared to those fed the GW diet. The WW diet, regardless to the method of inclusion, had no effect (P > 0.05) on the populations of Lactobacillus and Bacteroides spp. compared with the GW diet. The Bifidobacterium spp. population was higher (P < 0.05) in birds fed the GW diet compared with WW feeding, regardless of the method of inclusion. A reduction (P < 0.05) in the numbers of pathogenic Clostridium and Campylobacter spp. were observed in caecal samples from birds fed WW diets, regardless of method of inclusion, compared with those fed the GW diet, which was attributed to increased gizzard activity. Birds fed WW diets, regardless to the method of inclusion, showed a reduction in gizzard pH (P < 0.05), microbial gas production (P < 0.05), and an increase in gizzard weight (P < 0.05) relative to the GW treatment. The results indicated that the gizzard has an important function as a barrier organ, one that prevents pathogenic bacteria from entering the distal digestive tract.

Mannan from yeast has been demonstrated to limit infection in animals susceptible to gastrointestinal infection, including pigs, poultry and cows, by blocking the mechanism by which gram-negative bacteria adhere to and invade the intestines. Enterotoxigenic Escherichia coli (ETEC) cause post weaning diarrhoea (PWD) which results in poor weight gain and potential death at great economic cost to the farmer. A mannan rich fraction (MRF) was assessed in vitro for its impact on ETEC infection of HT-29 intestinal cell line. Gene expression markers for inflammation (TNFα and IL-1β) and TLR4 (TICAM-1 and LY96) associated recognition of bacteria were significantly elevated following exposure to E. coli alone, but not in combination with MRF compared to the control. HT-29 cells exposed to MRF alone demonstrated significantly reduced expression of immune signalling genes IRAK1, IRF7 and JUN when compared to the control. HT-29 cell protein abundance for TNFα and TLR4 associated proteins were significantly increased in response to E. coli exposure alone while no significant change was observed for MRF treatment with E. coli infection. E. coli adhesion to HT-29 cells was significantly decreased with addition of MRF compared to E. coli infection alone. The action of MRF demonstrated its potential capacity to limit infection on an in vitro level through blocking bacterial interaction with the intestines that leads to infection as marked by a reduction in proinflammatory responses. MRF on its own demonstrated potential anti-inflammatory effects on intestinal cells with the reduction of proinflammatory responses observed.

Inorganic trace mineral salts in the premix have a detrimental effect on the stability of vitamins due to redox reactions. A study was conducted to investigate the effect of dietary supplementation of different levels of vitamin premix with different mineral premixes on the performance and bone characteristics of broilers. A 2 x 2 factorial dietary treatment was used with two levels of vitamins and two types of minerals in the premix. A total of 1056, one-day old chicks were randomly assigned to four dietary treatments with 12 replicate pens of 22 chicks for 28 d. An interactive effect between vitamin levels and mineral sources on weight gain and feed intake of chickens was detected. Chickens fed the diet containing 100% vitamin premix with either source of mineral premix had higher (P < 0.01) weight gain and feed intake than those fed the diet containing 30% vitamin premix with either source of mineral premix. However, the chickens fed the diet containing the 30% vitamin premix with the organic minerals had higher (P < 0.01) weight gain and feed intake than those fed the diet containing 30% vitamin premix with inorganic minerals. Chickens fed the diet containing organic mineral premix had lower (P < 0.05) mortality and feed to gain ratio and higher (P < 0.01) bone breaking strength and ash content of tibia than those fed the inorganic mineral premix treatment. Chickens fed the diet containing 100% vitamin premix had higher (P < 0.01) breaking strength of femur and tibia ash than those fed the diet containing 30% vitamin premix. The results from this trial indicated that total replacement of inorganic trace minerals with organic minerals can increase the storage stability of vitamins in feed premixes containing both vitamins and trace minerals, which is reflected in better growth performance in poultry.

This study evaluated the effects of three different thermostable phytase variants, based on the AppA gene from E. coli (AppAT1, AppAT2 and AppAT3) on growth performance, nutrient digestibility and bone mineralisation in broiler chickens at inclusion levels of 250 and 500 FTU/kg. The eight treatment groups included a positive control (PC) which was sufficient in Ca and P, a negative control (NC, the same basal formulation as the PC, but reduced in Ca and P), and NC supplemented with AppAT1 at 250 and 500 FTU/kg (AppAT1-250 and AppAT1-500), AppAT2 at 250 and 500 FTU/kg (AppAT2-250 and AppAT2-500) and with AppAT3 at 250 and 500 FTU/kg (AppAT3-250 and AppAT3-500). Over the entire feeding period, body weight (BW) and average daily gain (ADG) were significantly higher in the PC group, with all phytase supplemented groups being statistically the same, compared to the NC group. Feed conversion (FCR) for the PC-fed birds (1.479) was significantly (P<0.05) better compared to the NC birds (1.582) and those fed the AppAT3-250 diet (1.523). Reduced levels of Ca and P in the NC group led to significantly (P<0.05) lower tibia ash (40.9%) compared to the PC group (47.4%). Birds fed the phytase diets had significantly higher tibia ash compared to the NC birds, with those from the AppAT2-500 and AppAT3-500 groups being statistically the same as the PC group. Diets AppAT1-500, AppAT2-250, AppAT2-500 and AppAT3-500 significantly increased Ca digestibility compared to the NC. Apparent total track digestibility (ATTD) of P was improved for AppAT1-500 and AppAT2-250. The ATTD of Ca and P for all of the phytase supplemented groups reached the same level of the PC and AppAT1-500 group. It was concluded that adding any of the phytases tested, especially when included at 500 FTU/kg to a feed reduced in Ca and P, led to improved performance and bone mineralisation back to the same levels as seen for the Ca and P sufficient diet.