A series of experiments were conducted to examine protein digestion in the young bird and the physiological changes that affect protein digestion as the bird matures. Trial one determined the effect of age on pH of the gastrointestinal tract. The results showed that the pH of the proventriculus and gizzard decreases with age suggesting that gastric acid secretion increases proportionally with age and this may impact protein digestion. Experiment two examined the effect of age on ileal amino acid (AA) digestibility of feed ingredients. AA digestibility increased from 5 to 21 d and the degree of improvement differed among ingredients and specific AA. This finding coupled with the low AA content of some ingredients demonstrates the importance of using appropriate nutrient digestibility values for young birds when formulating pre-starter and starter diets. Experiment three determined the acid binding capacity (ABC) of feed ingredients and the effect of formulating diets based on ABC on diet ABC, gastrointestinal pH and performance. The research confirmed dramatic differences in ABC among ingredients and that diets could be formulated on the basis of ingredient ABC. However, the range in diet ABC was less than predicted suggesting interactive effects among ingredients. Intestinal pH was reduced however broiler performance was not improved when diets low in ABC were fed. Experiment four examined the effect of diet acidification with HCl on diet ABC, gastrointestinal pH, ileal amino acid digestibility and broiler performance. Improvements in performance and reductions in mortality were observed when broilers were fed acidified diets. Adding acid to diets did not improve AA digestibility and therefore was not the reason for improved performance indicating an alternative mechanism of action. It is concluded that acid production by the proventriculus of young birds is low and increases with age however this does not impact protein digestion. Methods of improving performance of broiler chickens may include diet acidification however this is not the effect of remedying the low acid production by young birds. Therefore, alternative mechanisms are positively affecting broiler performance.

Broiler breeders experience a natural decline in fertility levels as a flock ages. A male management practice such as double interspiking could be applied to counteract this decline. Our objective was to investigate the effects of double interspiking on flock fertility, testosterone concentrations, stress responses, and behavioral responses of broiler breeders in heat stressed environments. Two hundred and eighty-eight broiler breeder pullets and thirty-six broiler breeder roosters (Ross 708) were assigned to three groups at 21 weeks of age (WOA). All three groups were housed in slatted floor pens in which room temperature cycled from 23.8 to 30 C to mimic heat stressed environments. Double interspiking was carried out between two pens at 42 and 52 WOA. Beginning at 32 WOA, eggs were set every two weeks, candled at day 12, and percent fertility calculated. Concentrations of the hormones testosterone and corticosterone (CS) were measured by radioimmunoassays at specific time points in the experiment. Lymphocytes and heterophils were counted in order to calculate heterophil:lymphocyte (H:L) ratios. Behavior was monitored with Panasonic video cameras which recorded video footage using the Noldus MPEG Recorder from 1900 hr to 2100 hr at specific time points. Recordings were analyzed, and frequency of specific behavioral responses of individual (preening, feather ruffling, wing flapping), male-to-male (fighting, pecking, retreating), and male-to-female (attempted and completed mating) behaviors were assessed. The introduction of unfamiliar roosters resulted in a fertility increase (P<0.01) between control and spiked birds after the first interspike and a sustainment of fertility levels after the second interspike. Testosterone concentrations declined (P<0.0001) from 1.95ng/mL to 0.11ng/mL as the birds aged. Corticosterone concentrations differed among bird groups and was elevated (P=.0333) for both groups that were interspiked. H:L ratios were also different among bird groups with all birds housed in the interspiked rooms showing higher ratios. Double interspiking increased the occurrence of male-to-male interactions, but there were no significant differences in male-to-female or individual behaviors. Regardless of treatment, there was a decrease in male-to-female behaviors as the birds aged. Double interspiking does show promise as a tool to increase fertility levels in a broiler breeder flock.

Heart rate is tonically regulated by the two branches of the autonomic nervous system (ANS); parasympathetic activation decreases heart rate while sympathetic activation increases it. Previous studies on the ANS in chickens have focused mainly on embryonic development, but it is largely unknown what happens in the weeks following hatching. The present study focused on the development of the autonomic nervous system in 2 and 5 week old broiler and Red Junglefowl (RJF). Since broilers are less fearful, less stressed and less active than their wild ancestor RJF, a possible domestication effect on the sympathetic nervous system was investigated by evaluating both physiological and behavioural responses during stress. I found that the heart is mainly under control from the sympathetic nervous system in 2 and 5 week old broiler and RJF as propranolol significantly decreased heart rate during baseline and stress conditions while injection of atropine had little or no effect on baseline heart rates. When the adrenergic tone was blocked, heart rate still increased during stress, more so in 5 week old birds than in 2 week old birds. This suggests that some other physiological regulatory mechanism with fast recruitment is involved in the stress response and it matures in the weeks following hatch. No differences in behaviour between broiler and RJF were observed when the sympathetic nervous system was blocked. As both breeds show similar responses, a domestication effect on the ANS from these results cannot be confirmed.

The aim of this study was to investigate the impact of Biomin P.E.P. – 1000 on the total quantity of lipids and triglycerides in blood serum of broiler chickens, also to analyze the impact of the preparation on the dynamics of growth and meat qaulity of birds. The results of our study show taht under the influence of phytogenic preparation Biomin P.E.P. – 1000 the content of total lipids and trigycerides in the blood serum of the broiler chickens at the age of 21 days increased, respectively, by 1,93 – 4,73 g/l and 0,22 – 1,07 mmol/l as compared to the control group. At the age of 42 days it increased: lipids by 0,82 – 1,61 g/l and triglycerides by 0,3 – 0,83 mmol/l as compared to the control group. In the influensce of this preparation the weight of broiler chickens increased by 9,92 – 10,62 % as compared to the control group. The testing of meat chemical composition showed positive influence of Biomin P.E.P. – on the quality of broiler chicken meat.

Darbo tikslas - nustatyti probiotikų, gautų iš pieno rūgšties bakterijų kamieno Pediococcus acidilactici MA 18 5 M, prebiotikų fruktooligosacharidų ir nekrakmolinius polisacharidus skaldančių fermentų įtaką žiurkių ir viščiukų broilerių virškinimo procesams, viščiukų broilerių produktyvumui ir mėsos juslinėms savybėms. Darbo metu atlikti moksliniai eksperimentai siekiant palyginti skirtingų vienkamerinių gyvūnų – žiurkių ir viščiukų broilerių virškinimo procesų kitimą šeriant ir lesinant juos probiotikų, prebiotikų, NKP skaldančių fermentų ir jų kombinacijų priedais. Šiame darbe atlikti išsamūs moksliniai tyrimai, kurių metu pagal vienodas bandymų schemas vykdyti eksperimentai su laboratoriniais gyvūnais (žiurkėmis) ir viščiukais broileriais. Vykdyti palyginamieji tyrimai, kurie gali būti naudojami kaip modelis tiriant naujus pašarų priedus. Pirmą kartą ištirta probiotikų, prebiotikų ir NKP skaldančių fermentų įtaka žiurkių ir viščiukų broilerių aklosios žarnos chimuso bakterinių fermentų, apsprendžiančių kancerogeninių metabolitų susidarymą, aktyvumams ir viščiukų broilerių mėsos juslinėms savybėms. Be to, nustatyta šių zootechninių pašarų priedų įtaka viščiukų broilerių produktyvumui ir jų fiziologinei būklei. / The aim of the present study is to determine the effect of probiotics lactic acid bacteria, produced from strain Pediococcus acidilactici MA 18 5 M, prebiotics fructooligosaccharides and non-starch polysaccharides (NSP) hydrolyzing enzymes on digestive processes of rats and broiler chickens, productivity and sensory attributes of the meat of broiler chickens. Three studies to determine the digestive processes of two different species of monogastric animals such as rats and broiler chickens fed diets supplemented with probiotics, prebiotics and non-starch polysaccharides (NSP) hydrolyzing enzymes were performed. The studies with laboratory animals (rats) and broiler chickens were performed according to the same experimental scheme. The comparable studies, which can be used as model for analysis of new zootechnical feed additives, were performed for the first time. The effect of probiotics, prebiotics and NSP hydrolyzing enzymes on activity of caecal chymus bacterial enzymes, which might play a role in activation of procarcinogens in large intestine of rats and broiler chickens were determined for the first time. Due to production of health, safe and high quality poultry products, the effects of these zootechnical feed additives on sensory attributes of the meat of broiler chickens were determined for the first time.

No description available.

Incorporation of full-fat flaxseed, and to a lesser extent, canola seed in diets to produce n-3-enriched products has attracted interest in the poultry industry. However, high amounts of nonstarch polysaccharides (NSP) in oilseeds compromise their nutritive value. The objectives of the current research were to develop enzyme supplements effective in cell wall depolymerization and viscosity reduction, particularly in flaxseed; to evaluate the effects of enzyme addition and feed processing on oil utilization and egg n-3 fatty acid deposition in broiler chickens and laying hens fed oilseed-containing diets; to characterize the NSP hydrolysis products and to investigate the effects of diet type and enzyme addition on growth performance and the incidence of necrotic enteritis (NE) in broiler chickens challenged with Clostridium perfringens. Results showed that diets containing high levels of flaxseed reduced egg production and shell quality in laying hens, and impaired final body weight and feed conversion ratio (FCR) in broiler chickens. Reducing flaxseed particle size via grinding did not improve the growth performance of broiler chickens, whereas diet pelleting showed more pronounced and beneficial effects in improving the nutritive value of flaxseed, particularly when intact seeds were used. Multicarbohydrase supplementation resulted in a significant depolymerization of cell wall polysaccharides in soybean, canola and flaxseed meals, which was followed by the production of water-soluble NSP hydrolysis products, and the reduction of flax mucilage viscosity in vitro was also evident. Enzyme addition to flaxseed-containing diets improved FCR of broiler chickens and egg production performance of laying hens, and facilitated egg n-3 fatty acid deposition. The C. perfringens challenge caused intestinal NE lesions and increased the mortality of broiler chickens with the highest NE mortality and intestinal C. perfringens counts observed in those fed flaxseed-containing diets. Enzyme supplementation to diets containing high levels of water-soluble NSP (wheat/barley- or wheat/barley/flaxseed-based) facilitated post-disease compensatory growth in pathogen challenged birds. This was accompanied by a numerical reduction of intestinal C. perfringens by 1.4 log10 cfu/g in birds fed the flaxseed-containing diets. Such findings indicated that enzyme addition may be used as a nutritional strategy to reduce the risk of NE development in broiler chickens.

The objectives of these experiments were to evaluate the main effects and interactive effects between dietary supplementation of a mannan oligosaccharide based product, Actigen® (ACT), and different levels of threonine in monogastrics, as evidenced by growth parameters, immune function, and intestinal health characteristics. In nursery piglets, ACT supplementation decreased average daily feed intake (P=0.04), but had no effect on body weight or feed conversion ratio. There were no noted differences between threonine levels on performance traits. There were no consistent differences in complete blood count or cytokine gene expression profiles in the blood. The highest level of threonine, 77% true ileal digestible threonine:lysine (Thr:Lys), increased villus height (P=0.007) and villus height:crypt depth (P=0.01). The lowest level, 57% Thr:Lys, decreased villus surface area (P=0.04) and goblet cell density (P=0.04). Supplementation with ACT increased total goblet cell area (P=0.02) and density (P=0.05). There were no interactions observed between ACT and Thr:Lys levels. In broiler chicks, feeding a diet containing 0.56% threonine decreased body weight (PPPP=0.07). On d 7, birds supplemented with ACT had heavier spleens as a percentage of body weight (P=0.01) compared to no ACT. When adjusted for body weight, the 0.56% threonine fed birds had smaller spleens (P=0.05) on d 7 when compared to the other threonine levels. Humerus (PPP=0.04) and birds fed 0.56% threonine had a higher concentration of potassium (PP=0.03) and few goblet cells (P=0.04) on d 7 when compared to the other threonine levels. In d 21 jejunum, supplementation with ACT reduced apical width (P=0.03) and surface area (P=0.02). An interaction was observed between ACT and threonine level in the jejunum on d 21 on basal width (P=0.03) and surface area (P=0.02), indicating that in diets lacking ACT, excess threonine increased villus size. Overall, ACT and threonine acted primarily independently to modulate the intestinal architecture of both nursery piglets and broiler chicks. However, in broiler chicks ACT and threonine interacted to alter villus size. These results indicate that ACT and threonine have direct effects on the intestines of monogastrics.

The parental stock of meat type chickens (broiler breeders) are commonly feed restricted to decrease their rapid growth and the issues associated with it. Among these birds, chronic hunger and stress are the most prominent welfare concerns and mass heterogeneity within flocks a major management challenge. The present study compared small and large broiler breeders of the same age within a flock, with the hypothesis that small birds would show signs of poorer welfare indicated by higher corticosterone concentration and heterophil/lymphocyte ratio as a consequence of higher experienced feed restriction due to competition. It also aimed to characterize morphometric differences between small and large birds within flocks as well as between birds on different feeding regimens; skip-a-day vs. every-day-fed. Heterophil/lymphocyte ratio at 4 weeks was significantly higher in large birds compared to small birds, but corticosterone concentration did not differ. Relative mass of the upper gastrointestinal tract, pancreas and liver of small birds at 4 weeks of age were significantly larger, while relative muscle and gizzard fat mass were significantly lower compared to large birds. 12 weeks old skip-a-day fed birds largely followed the pattern of 4 weeks old small birds. In the present study, no clear signs of poorer welfare in small broiler breeders could be seen and the morphometric differences might suggest different ways to cope with feed competition. A larger gastrointestinal tract might indicate long-term investments and maybe that smaller broiler breeders, and skip-a-day fed birds, are better habituated to feed restriction.

The thermoneutral zone (TNZ) curve lies between the ambient temperatures (Ta) where an endothermic animal uses the least amount of energy to maintain a balance between the heat production from the animal’s own metabolism and the heat lost to the environment. If the animal is exposed to Ta’s over the upper critical temperature (UCT), which is the highest temperature that is still in the TNZ, the animals have to use energy to cool down. If they are exposed to temperatures lower than the lower critical temperature (LCT), which is the lowest temperature that is still in the TNZ, the animal have to use energy to warm up. In the present study oxygen consumption was measured at different Ta’s to determine the TNZ in two and three week old broiler chickens (Gallus gallus domesticus). Two different protocols were used and compared, a pseudorandom protocol in which chickens were exposed to seven temperatures in two hour periods for each run and a more typical progressive protocol in which Ta decreased gradually, one or two degrees per hour. The TNZ in two weeks old chickens was between 30.7 ˚C- 36.4 ˚C and between 28.8 ˚C- 32.7 ˚C in the three weeks old chickens. In chickens the TNZ shifts remarkably during the first few weeks of life towards lower temperatures as the animals acquire thermoregulatory competence. The method with a pseudorandom protocol takes more factors, like activity, into consideration than a typical progressive protocol.