Effect of the Length of Feed Withdrawal on Weight Loss, Yield and Meat Color of Broiler

Effect of chamomile (Matricaria chamomilla L.), linden (Tilia cordata Mill.), and green tea (Camellia sinensis L.) aqueous extract administration in the drinking water during pre-slaughter feed withdrawal period in broiler chickens

Feed withdrawal (FW) and other pre-slaughter stressors have detrimental effects on the meat quality of broiler chickens. Herbal extracts can be used for their sedative effects to reduce the harmful impacts of pre-slaughter stress on broiler chickens. This study aimed to investigate the effect of chamomile (CAE), linden (LAE), and green tea (GAE) aqueous extracts (AE) in drinking water during the pre-slaughter FW period on the meat and liver quality, serum corticosterone level, and some cecal microorganisms of broilers. A total of 450 male and female 42-day-old chickens were allocated to a completely randomized design with five treatment groups and two sexes in six replicates, 12 birds (six male and six female) for each replicate. Treatment groups were chickens offered ad libitum feed and drinking water (control, CT), broilers exposed to FW for 10 h before the slaughter with unsupplemented drinking water (FW), with drinking water supplemented 50 ml/L CAE, LAE, and GAE. Chickens that experienced FW had lower (P < 0.001) slaughter body weight, carcass, gastrointestinal tract (GIT) and inner organ weights, and GIT length (P = 0.002). However, the dressing percentage was higher (P < 0.001) in FW and AE groups than CT group. The FW increased (P < 0.001) the ultimate pH of thigh meat compared with the CT group. The FW also decreased (P = 0.026) the lightness (L*) value of thigh meat of broilers, although CAE and LAE did not change the L* value compared with the CT group. Similarly, the redness (a*) value of thigh meat was lower (P = 0.003) in chickens exposed to FW but was not affected by GAE administration. However, FW or AE did not impact the serum corticosterone level and cecal microbial loads in broiler chickens. The obtained result showed that CAE, LAE, or GAE can be used in drinking water to reduce the harmful effects of FW on the meat quality of broiler chickens.

Effect of emulsifier and multicarbohydrase enzyme supplementation on performance and nutrient digestibility in broiler diets containing rapeseed meal

The aim of this study was to determine the effect of emulsifier and multicarbohydrase enzyme supplementation on performance, nutrient utilization, and apparent metabolizable energy-nitrogen (AME_N) value of broiler diets containing rapeseed meal (RSM) as well as their influence on the gut morphological structures, excretion of total and free sialic acid, and cecum concentration of short-chain fatty acids (SCFAs) in broiler chickens. A total of 384 male broiler chicks were assigned to four dietary treatments. The diet of the control treatment (CON) consisted of soybean, maize, and RSM (5% in starter, 7% in grower, 15% in finisher) with soybean and palm oils. The diets used for the experimental treatments were the control diet supplemented with an emulsifier (EMU), enzyme (ENZ), or both (EMU + ENZ). The duodenum (n = 10/treatment) and ileum (n = 10/treatment) digesta samples were assessed to determine nutrient digestibility: crude protein (CP), ether extract (EE), starch, Ca. Throughout the experimental period, EMU + ENZ treatment indicated the lowest total average feed intake and feed conversion ratio, with the highest average weight gain among the studied treatments (P < 0.05). The EMU + ENZ treatment also resulted in higher (P < 0.05): apparent prececal digestibility (APD) of CP, total tract neutral detergent fibre (NDF) degradation, apparent total tract digestibility (ATTD) of EE, villus height to crypt depth ratio (P < 0.1). The highest APD of EE was noted in the EMU treatment (P < 0.05). No significant differences were found in the AME_N values of the diets. A greater jejunum villi surface area was found in groups supplemented by enzyme compared to CON (P < 0.05). The EMU + ENZ treatment presented lower sialic acid excretion in the ileum and concentration of cecum SCFAs compared to the CON treatment (P < 0.05). The obtained results indicate that simultaneous usage of additives had beneficial effect on production parameters, nutrient digestibility, NDF degradation, as well as gut mucosa morphology. Based on the SCFAs concentration results, separate or simultaneous addition of emulsifier or/and enzyme did not provoke excessive fermentation activity of cecal bacteria.

Influence of pre-slaughter fasting time on weight loss, meat quality and carcass contamination in broilers

Objective

An experiment was conducted to determine the appropriate fasting time prior to slaughter for broilers in floor-feed and scatter-feed mode.

Methods

On 21 d since hatching, 120 Arbor Acres broilers were divided into floor-feed and scatter-feed groups, chicks from each group were further assigned to feed withdrawal treatments for 0, 4, 6, 8, and 10 h. Some resultant indicators such as carcass contamination, body weight loss, meat quality of 54-day-old broilers were measured.

Results

It appears that longer feed withdrawal increased weight loss, lightness, drop loss of meat but reduced pH. A significant higher weight loss and lightness for both floor-feed and scatter-feed chicks coincided after 6 to 10 h feed withdrawal (p<0.05). pH for breast muscle at 45 min postmortem reduced when chicks of scatter-feed were fasted 6 and 10 h, while the reduction of floor-feed group occurred only in 10 h (p<0.05). A noticeable effect of feed withdrawal on drop loss occurred after 10 h fasting in scatter-feed of which drop loss were significantly higher than that for other groups including control (p<0.05). The change of contamination propensity revealed that 6 to 10 h fasting significantly reduced the likelihood of carcass contamination under both floor-feed and scatter-feed (p<0.05). Net weights of intestinal contents for gizzard were significantly reduced after feed deprived for 10 h in floor-feed and 6 and 10 h in scatter-feed (p<0.05). The decrease for whole intestine occurred after floor-feed broilers have been without feed for more than 4 h, scatter-feed broilers for more than 8 h (p<0.05).

Conclusion

On the premise that poultry product properties and welfare were not significantly damaged, proper fasting time could reduce carcass contamination. Current data implied that 6 h fasting was recommendable for both floor and scatter feed pre-slaughter broilers.

Injury and mortality in broilers during handling and transport to slaughter

Multiple factors affect the risk of broiler injury and mortality during loading, transport, and lairage. These include the physical and pathophysiological condition of broilers before loading and the type of handling procedures used. The external environmental conditions have a major influence on the risk of mortality. Combinations of high stocking density, insufficient ventilation, and high temperature and humidity pose a risk of hyperthermia. Combinations of wet conditions, cold temperature, and air movement, increase the risk of hypothermia. However, protection from cold and wet conditions involves the use of side protection that restricts the trailer ventilation that can cause heat and moisture to build up in the load, increasing the risk of hyperthermia. Modular systems reduce the risk of injury and facilitate unloading into a lairage where temperature and ventilation can be controlled. The duration of loading, transport, and lairage increases the mortality risk. Deaths can occur during each stage and interactions between the duration of the preslaughter stages, the thermal environment, fasting, ill-health, and injury can reduce the physiological capacity of the birds to maintain homoeostasis resulting in exhaustion and death. Quality control and action on the identified risk factors should reduce injury and mortality during preslaughter handling and transport.

Factors affecting mortality risk during transportation of broiler chickens for slaughter in Atlantic Canada

Mortality of broilers during transport and lairage before slaughter represents an economic loss to the poultry industry and a welfare issue that needs to be addressed. In Canada, broilers can be transported long distances and be exposed to environmental factors, such as cold temperatures, that can affect the percentage of dead-on-arrivals or DOAs. Slaughter plant records for loads transported over a 19-month period in 2009-2010 were examined to identify factors affecting mortality risk (% DOA) during transportation from the rearing barn to the slaughter plant. Information from 2007 loads was analysed using a multilevel linear model. Most of the variation in the mortality risk occurred at the load level rather than at the producer or barn level. There were significant effects of bird sex, age and weight, catching team, journey duration and holding barn duration on mortality risk. The following environmental risk factors increased mortality risk: cold temperatures during the journey and in the holding barn, low crate stocking density during journeys at cold temperature and increased trailer temperature when in the holding barn. The analyses identified risk factors that can be used to refine management practices to mitigate some of the mortality risk. Increased mortality in some loads was associated with environmental conditions that caused deaths from hypothermia, whereas in other circumstances, some deaths likely occurred from hyperthermia. The climatic conditions in Atlantic Canada were responsible for significant risk factors that affected the mortality risk. Although refinement of the management practices described in this study, such as reduced journey and lairage durations, and increased crate stocking density can mitigate some of the mortality risk, the extreme cold conditions experienced during some parts of the year exceeded the capacity of the systems of transportation used to provide environmental conditions that minimise mortality.

The effects of the supplementation of Bacillus subtilis RX7 and B2A strains on the performance, blood profiles, intestinal Salmonella concentration, noxious gas emission, organ weight and breast meat quality of broiler challenged with Salmonella typhimurium

An experiment was conducted to evaluate the effects of B. subtilis RX7 and B. subtilis B2A on growth performance, blood profiles, intestinal Salmonella population, noxious gas emission, organ weight and breast meat quality of broilers under S. typhimurium challenge. A total of 120, one-day-old Ross 308 male broiler chicks were assigned to four dietary treatments, composed of six replications, with five birds per replication, for 10 day. The dietary treatment groups were negative control (NC; no antibiotic, no B. subtilis), positive control (PC; NC + 0.1% virginiamycin), B. subtilis RX7 (NC + 0.1% B. subtilis RX7 1.0 × 10(9) cfu/g) and B. subtilis B2A (NC + 0.1% B. subtilis 1.0 × 10(9) cfu/g). All birds were orally challenged with 2 ml suspension, containing 10(4) cfu/ml of S. typhimurium KCCM 40253. Results indicated that the body weight gain, feed intake and feed conversion did not differ, among all comparative treatments. Serum haptoglobin concentration was lower in Bacillus treatments (RX7 + B2A) than the NC treatment (p < 0.05). Intestinal and excreta Salmonella number, and excreta ammonia gas emission in the PC treatment or Bacillus treatments, was lower than the NC treatment (p < 0.05). Breast pH, colour and water-holding capacity were not affected by supplementation of B. subtilis RX7 and B2A. However, drip loss at 1 day post-slaughter from birds fed with B. subtilis RX7 and B2A decreased, compared with the positive control birds (p < 0.05). Relative gizzard weights of birds fed B. subtilis RX7 and B2A were significantly higher than the NC birds under S. typhimurium challenge. It is concluded from the results that B. subtilis RX7 and B2A increased the gizzard weight and decreased the intestinal and excreta Salmonella population and excreta ammonia gas, and drip loss of breast meat after being stored for 1 day, under stress caused by the S. typhimurium challenge.