The gut health of poultry is closely associated with feeds and feeding. The experiment was conducted to the effect of crude glycerol addition to diets of male broilers on the bacterial microflora and morphology of their small intestines (duodenum, jejunum and ileum). A total of 120 Ross 308 broiler chicks received diets containing 0% (GLY 0), 4% (GLY 4) or 8% (GLY 8) crude glycerol for 42 days. The presence of Coliform bacteria and Enterobacteria was reduced in the duodenal tract of the broilers of GLY 4 (P<0.001); however, the presence of Staphylococci/Micrococci in the GLY 8 was reduced relative to the other groups (P<0.001). The presence of Salmonella spp. decreased in conjunction with the increasing quantities of glycerol (P<0.001). Analysis of the data regarding gut morphology (epithelial cell thickness, villi length and width, and crypt length and width) indicated that the glycerol levels fed to the different groups of broilers represented statistically different results in the small intestine. In general, whereas the diet with 4% glycerol statistically affected the investigated parameters of the gut, the diet with 8% glycerol statistically affected some segments of the broiler intestines.

The aim of the present study was to evaluate the feasibility of an antimicrobial peptide, cecropin A(1-11)-D(12-37)-Asn (CADN), as an alternative to antibiotic growth promoter (AGP) in poultry diets. A total of 1500 14-d-old indigenous male chickens (222 (sd 13) g) were randomly allocated to five groups with five replicate cages of sixty birds each, and fed ad libitum five grower diets and subsequently five finisher diets for 14 d each. The diets were made up by supplementing their basal diets with a CADN liquid sample (CADNL) at 0, 2, 4, 6 and 8 ml/kg, respectively. During the feeding period, a metabolic experiment was carried out to determine the apparent digestibility of diethyl ether extract, nitrogen retention and apparent metabolisable energy of the diet sample fed to each cage of chicks. At the end of the feeding experiment, one chick from each cage was killed for bacteriological, light microscopic and scanning electron microscopic examination of the intestinal villi. CADN had a negative linear, positive quadratic and negative linear effect on feed intake (F), weight gain (G) and feed:gain ratio (F:G), respectively, for the growers; it had a quadratic effect on F, G or F:G for the finishers; it increased nutrient utilisation for both growers and finishers; it decreased aerobic bacterial counts in both jejunal and caecal digesta in a dose-dependent manner; it enhanced intestinal villus heights in a dose-dependent manner and made the duodenum villi of the CADNL8 group at 42 d appear as a netted leaf-like structure. CADN is therefore a possible alternative to AGP in broiler feeds.

A study was conducted to evaluate a natural carbohydrate fraction Actigen™ (NCF), derived from mannanoligosaccharide, in feed on growth performance, intestinal morphology and goblet cell number and area of male broilers'. Dietary treatments included: 1) control diet (antibiotic and NCF free), 2) NCF at 200 g/t, 3) NCF at 400 g/t, and 4) NCF 800 g/t. Two hundred and forty birds were placed into 12 replicate pens per treatment (5 birds/pen), sixty birds per treatment. Body weight and feed intake were recorded weekly up to day 42. At this time a 2.5cm section of jejunum and duodenum were excised post mortem for morphological analysis. Birds fed 200 g/t and 800 g/t NCF were significantly (P < 0.01) heavier from day 14 onwards than the control birds. Feed intake was significantly higher in birds fed 200 g/t NCF compared to those fed the control at 21 and 35 days (P < 0.05). Diets containing 200 g/t and 800 g/t of NCF significantly decreased broiler feed conversion ratio (FCR) compared to the control in the first phase (1–14 days) (P < 0.01) and levels of NCF decreased FCR (P < 0.05) in the second phase (15–28 days). NCF had no significant effect on villus height, villus width, crypt depth or villus to crypt ratio in either duodenum or jejunum. NCF did not significantly affect goblet cell area or goblet cell number in the duodenum, however, in the jejunum, 800 g/t NCF significantly (P < 0.05) increased goblet cell area over the control. In conclusion, NCF showed a positive effect on broiler performance in the starter and grower phases, and increased goblet cell area in the jejunum, suggesting higher levels of mucin production. This indicated that the performance benefit of NCF could be age-dependent, with younger birds responding more than the older ones. There were no additional benefits to performance when feeding NCF for a longer period (after 28 d of age), however it is postulated that birds fed NCF would have greater defence to pathogenic challenge through increased storage capacity of mucin.

The synthetic disaccharide lactulose is known to improve the intestinal microflora by stimulating the growth of selected probiotic bacteria in the gut. In our experiment the effects of lactulose in combination with the probiotic bacteria Enterococcus faecium on growth performance and morphology of the bovine intestine were examined. Calves aged 39 ± 2 days were randomised to three feeding groups (no. = 14 each group): control (L0), fed milk replacer (MR) containing E. faecium; a lactulose group (L1) containing additional 1% lactulose and a second lactulose group (L3) containing 3% lactulose dry matter. The calves were weighed weekly. After 19 weeks the calves were slaughtered and tissues were collected for histological studies. The average daily live weight gain tended to be higher (P < 0.1) for L3 (1350 g/day) than L0 (1288 g/day). Compared with L0, a reduction (P < 0.001) of ileal villus height due to lactulose treatment of approximately 14% in group L1 and 20% in L3 was determined. A significant decrease in the depth of the crypts about 12% in L1 and 8% in L3 was detected in the caecum. The surface area of lymph follicles from Peyer's patches was decreased by lactulose treatment. Results show that lactulose has an effect on the morphology of intestine. A significant effect on growth performance can not be confirmed. However, results permit the conclusion that lactulose feeding has the tendency to increase growth performance.