Effects of oxygen concentration during incubation and broiler breeder age on embryonic heat production, chicken development, and 7-day performance

Older breeder flocks produce eggs with a relatively larger yolk and thereby a higher nutrient availability than young breeder flocks. To optimise nutrient utilisation and embryonic development throughout incubation and posthatch period, embryos originating from older breeder flocks may require a higher oxygen availability. The current study investigated effects of broiler breeder flock age and incubational oxygen concentration on embryonic metabolism and chicken development until 7-day posthatch. Similar sized eggs of a young (28-32 week) or old (55-59 week) Cobb 500 breeder flock were incubated at one of three oxygen concentrations (17%, 21% or 25%) from day 7 of incubation until 6 h after emergence from the eggshell. Posthatch, chickens were reared until 7 days of age. Egg composition at the start of incubation, heat production during incubation, and embryo or chicken development at embryonic day (ED)14 and ED18 of incubation, 6 h after hatch and day 7 posthatch were evaluated. An interaction was found between breeder age and oxygen concentration for yolk-free body mass (YFBM) at ED18. A higher oxygen concentration increased YFBM in the old breeder flock, whereas no difference was found between 21 and 25% oxygen in the young breeder flock. Yolk size was larger in the old compared to the young flock from ED0 until 6 h after hatch. Breeder flock age did not affect YFBM at ED14 and 6 h after hatch nor daily embryonic heat production, but there were some effects on relative organ weights. Chickens of the old compared to the young breeder flock showed a higher weight gain at day 7, but at a similar feed conversion ratio (FCR). A higher oxygen concentration during incubation stimulated embryonic development, especially between 17% and 21% of oxygen, in both flock ages_. Although this growth advantage disappeared at 7 days posthatch, a low oxygen concentration during incubation resulted in a higher FCR at 7 days posthatch. Results indicated that breeder flock age seemed to influence body development, with an advantage for the older breeder flock during the posthatch period. Oxygen concentrations during incubation affected body development during incubation and FCR in the first 7 days posthatch. Although an interaction was found between breeder flock age and oxygen concentration at ED18 of incubation, there was no strong evidence that nutrient availability at the start of incubation (represented by breeder flock ages) affected embryo and chicken development at a higher oxygen concentration.

Interaction between eggshell temperature and carbon dioxide concentration after day 8 of incubation on broiler chicken embryo development

Carbon dioxide (CO₂) is considered to be an important factor during incubation of eggs. Effects attributed to higher CO₂ concentrations during experiment might be due to confounding effects of other environmental conditions, such as incubation temperature. To disentangle effects of eggshell temperature (EST) and CO₂ concentration, an experiment was conducted. A total of 630 Cobb 500 hatching eggs from 37 to 45 wk commercial breeder flocks were collected and incubated according to treatments. The experiment was setup as a complete randomized 2 × 3 factorial design, resulting in 6 treatments. From day 8 of incubation onward, broiler eggs were exposed to one of two EST (37.8 or 38.9 °C) and one of three CO₂ concentrations (0.1, 0.4 or 0.8%). Eggs were incubated in climate-respiration chambers and metabolic heat production was determined continuously. At day 18 of incubation and at 6 h after hatching, embryo and chicken quality were determined by evaluation of organ weights, navel condition, blood metabolites and hepatic glycogen. Hatching time and chicken length at 6 h after hatching showed an interaction between EST and CO₂ concentration (both P = 0.001). Furthermore, no effect of CO₂ concentration was found on embryo development or chicken quality. Metabolic heat production between day 8 and 18 of incubation was not affected by either EST or CO₂. At day 18 of incubation, an EST of 38.9 °C resulted in a higher egg weight loss, longer embryos, higher yolk free body mass (YFBM) and lower heart weight than an EST of 37.8 °C (all P < 0.008). At 6 h after hatching, an EST of 38.9 °C resulted in a higher residual yolk weight and lower YFBM, liver weight and heart weight than an EST of 37.8 °C (all P < 0.003). Lactate, uric acid and hepatic glycogen were not affected by EST at either day 18 of incubation or at hatch. Glucose was not affected by EST at day 18 of incubation, but at hatch, it was higher at an EST of 37.8 °C than at an EST of 38.9 °C (P = 0.02). It can be concluded that effects of CO₂ concentration (at concentrations ≤0.8%) on embryonic development and chicken quality appear to be limited when EST is maintained at a constant level. Moreover, a higher EST from day 8 of incubation onward appears to negatively affect chicken quality at hatch.

Both the rooster line and incubation temperature affect embryonic metabolism and hatchling quality in laying hen crossbreds

Effects of 3 eggshell temperatures (EST; 36.7. 37.8, and 38.9°C) in 2 genetic laying hen crossbreds (AB and BB; same hen line, different rooster line) on embryonic metabolism and hatchling quality were investigated. EST were applied from day 14.5 of incubation (E14.5) until hatching. The experiment consisted of 6 consecutive batches with eggs weighing between 59 and 61 g. Heat production was determined continuously from E14.5 onward. In fresh eggs, yolk weight tended to be higher (Δ = 0.28 g; P = 0.08) in the AB crossbred than in the BB crossbred. At E14.5 and E18.5, yolk-free body mass (YFBM) and residual yolk (RY) weight did not differ between genetic crossbred and EST. Hatching time after the start of incubation was not affected by genetic crossbred, but was longer in the 36.7°C (517 h) than in the 38.9°C (505 h), with 37.8°C in between (506 h). At 6 h after hatching, no differences between crossbreds were found for chicken quality parameters, such as chicken weight, chicken length, RY, YFBM, and organ weights, but heart weight was higher in the 36.7°C EST than in the other 2 EST (Δ = 0.24 to 0.30% of YFBM, P = 0.005). Intestinal weight was higher at 36.7°C EST than at 38.9°C EST (Δ = 0.79% of YFBM; P = 0.02), with 37.8°C EST in between. Heat production between E14.5 and E18.5 was higher in the AB crossbred than in the BB crossbred (Δ = 2.61%, P < 0.001) and regardless of crossbred higher at an EST of 38.9°C than at other 2 EST (Δ = 3.59% on average; P < 0.001). Hatchling quality determined at pulling (E21.5) was not affected by EST, but AB chickens were lighter (Δ = 0.46 g; P = 0.03), had less red hocks (Δ = 0.03; P = 0.02), more red beaks (Δ = 0.10; P < 0.001), and a higher (worse) navel score (Δ = 0.11; P < 0.001) than BB chickens. It can be concluded that not only incubation temperature, but also the rooster line appears to play a role in layer crossbred embryo metabolism and hatchling quality.

Diet density during the first week of life: Effects on growth performance, digestive organ weight, and nutrient digestion of broiler chickens

The current study aimed to investigate whether diet density affects growth performance and nutrient digestion during the first wk after hatch and digestive organ weight at 7 d of age. Effects were studied using a dose-response design consisting of 5 dietary fat levels (3.5, 7.0, 10.5, 14.0, and 17.5%). The dietary fat level was increased through soybean oil inclusion. Amino acids, minerals, and the premix were increased at the same ratio as dietary fat. Consequently, diets were kept neither isocaloric nor isonitrogenous. Broiler chickens were weighed on d 0 and d 7 after hatch, whereas feed intake was measured daily. Excreta produced from d 0 to d 7 was collected at d 7. Dietary dry matter and nitrogen metabolizability, as well as fat digestibility were calculated as an average over 7 days. Broiler chickens were sampled at d 7 to determine carcass yield, breast meat yield, and organ weights. Average daily gain (P = 0.047) and average daily feed intake (P < 0.001) decreased linearly as diet density increased, while gain to feed ratio increased linearly (P < 0.001). An increased diet density resulted in a linear decrease of crop, liver, and pancreas weight relative to body weight (BW; P < 0.05). Duodenum, jejunum, ileum, and cecum length (expressed as cm/kg of BW) and empty weight (as % of BW) increased linearly with increased diet density (P < 0.05). Dietary dry matter metabolizability decreased linearly as diet density increased (P < 0.001), whereas fat digestibility and nitrogen metabolizability were not affected (P > 0.05). In conclusion, one-week-old broiler chickens respond to increased diet densities by increasing intestinal weight and length, while decreasing liver and pancreas weight. This may be an adaptive response to cope with an increased nutrient concentration in the diet.

Effects of breeder age, broiler strain, and eggshell temperature on development and physiological status of embryos and hatchlings

Breeder age and broiler strain can influence the availability of nutrients and oxygen, particularly through differences in yolk size and shell conductance. We hypothesized that these egg characteristics might affect embryonic responses to changes in eggshell temperature (EST). This study aimed to investigate the effect of breeder age, broiler strain, and EST on development and physiological status of embryos. A study was designed as a 2 × 2 × 2 factorial arrangement using 4 batches of 1,116 hatching eggs of 2 flock ages at 29 to 30 wk (young) and 54 to 55 wk (old) of Ross 308 and Cobb 500. EST of 37.8 (normal) or 38.9°C (high) was applied from incubation d 7 (E7) until hatching. The results showed that breeder age rather than broiler strain had an influence on yolk size (P = 0.043). The shell conductance was higher in Ross 308 than in Cobb 500 (P < 0.001). A high EST resulted in a higher yolk free body mass (YFBM) compared to the normal EST at E14 and E16, but at 3 h after hatch YFBM was lower when eggs were incubated at high EST compared to normal EST (all P < 0.001). Cobb 500 eggs yielded embryos with a lower YFBM at E14, E18, and 3 h after hatch (all P < 0.05) than Ross 308 eggs. Breeder age had no effect on YFBM, but the RSY weight was higher in embryos from the old flock compared to the young flock embryos at E14 and E16 (both P < 0.05). A 3-way interaction among breeder age, strain, and EST was found, especially for incubation duration, navel quality, and relative heart and stomach weights at 3 h after hatch (all P < 0.05). Based on the results obtained, we conclude that oxygen availability rather than nutrient availability determines embryonic development, and the egg characteristics affected embryonic responses to changes of EST, especially for variables related to chick quality.

Effects of ambient temperature, feather cover, and housing system on energy partitioning and performance in laying hens

Environmental factors, such as ambient temperature (T), feather cover (FC), and housing system (HS), probably affect energy requirements of laying hens. Using a 3 × 2 × 2 factorial arrangement, interaction effects of T (11, 16, and 21°C), FC (100 and 50%), and HS (cage and floor housing) on energy partitioning and performance of laying hens were investigated. Six batches of 70 H&N Brown Nick laying hens, divided over 2 respiration chambers, were exposed to the T levels in three 2-wk periods. Heat production (HP) was determined by indirect calorimetry. The ME intake was calculated by subtracting energy in manure/litter from that in feed and wood shavings. The NE was calculated by subtracting HP from ME. The ME intake increased by 1% for each degree reduction in T. In hens with intact plumage, HP was not affected by T, whereas at decreasing T, HP increased in hens with 50% FC (P < 0.01). At 21°C, HP was not affected by HS, whereas in the floor system, HP at 16 and 11°C was 5.8 and 3.0% higher, respectively, than in cages (P < 0.05). The NE for production was 25.7% higher in cages compared to the floor system (P < 0.05). In cages, 24.7% of NE for production was spent on body fat deposition, whereas in the floor system, 9.0% of NE for production was released from body fat reserves. The ME intake was predicted by the equation (R(2) = 0.74) ME intake (kJ/d) = 612 BW(0.75) - (8.54 × T) + (28.36 × ADG) + (10.43 × egg mass) - (0.972 × FC). Hen performances were not affected by treatments, indicating the adaptive capacity of young laying hens to a broad range of environmental conditions.

Development and nutrient metabolism of embryos from two modern broiler strains

A progressive selection for broiler live and processing performance traits has changed broiler growth patterns during the post hatch period. However, limited information is available to understand whether changes have also occurred during the embryonic stages. This study aims to examine influences of broiler strain on nutrient availability, embryonic development, and nutrient metabolism during incubation. Hatching eggs of Ross 308 and Cobb 500 fast feathering were selected from breeder flocks aged 43 to 46 weeks at an egg weight range of 60 to 63 g. Eggs were obtained in 2 batches, 120 eggs per strain per batch. For each batch, 20 eggs per strain were used to determine egg composition and nutrient availability. The remaining eggs were incubated separately in one of 2 climate respiration chambers at an eggshell temperature of 37.8°C. The results showed that Ross 308 eggs had a higher yolk:albumen ratio with 0.9 g more yolk and 0.7 g less albumen than Cobb 500. Albumen + yolk of Ross 308 eggs had a higher dry matter (Δ = 0.24 g) and crude fat (Δ = 0.23 g) than that of Cobb 500 eggs, but a similar amount of crude protein. Albumen and yolk of Ross 308 eggs had a higher energy content (Δ = 8.9 kJ) compared to Cobb 500 eggs. At 3 h after hatch, Ross 308 chicks were 0.2 cm longer and had a 0.6 g heavier yolk free body mass (YFBM) than Cobb 500 chicks. During incubation, Ross 308 embryos used 13.9 kJ more energy than Cobb 500, and the efficiency of converting energy used to YFBM (EYFB) was approximately 7.6% lower compared to Cobb 500. Ross 308 chicks hatched approximately 4 h later and had less hepatic glycogen (Δ = 5 mg) than Cobb 500 chicks. It can be concluded that, Cobb 500 and Ross 308 differ in egg nutrient availability and have different trajectories for embryonic development and nutrient metabolism during incubation.

Differences in egg nutrient availability, development, and nutrient metabolism of broiler and layer embryos

Selection for production traits of broilers and layers leads to physiological differences, which may already be present during incubation. This study aimed to investigate the influence of strain (broiler vs layer) on egg nutrient availability, embryonic development and nutrient metabolism. A total of 480 eggs with an egg weight range of 62.0 to 64.0 g from Lohmann Brown Lite and Ross 308 breeder flocks of 41 or 42 weeks of age were selected in two batches of 120 eggs per batch per strain. For each batch, 30 eggs per strain were used to determine egg composition, including nutrient and energy content, and 90 eggs per strain were separately incubated in one of two climate respiration chambers at an eggshell temperature of 37.8°C. The results showed that broiler eggs had a higher ratio of yolk: albumen with 2.41 g more yolk and 1.48 g less albumen than layers. The yolk energy content of broiler eggs was 46.32 kJ higher than that of layer eggs, whereas total energy content of broiler eggs was 47.85 kJ higher compared to layer eggs. Yolk-free body mass at incubation day 16 and chick weight and length at hatch were higher in broilers compared to layers. Respiration quotient of broiler embryos was higher than layer embryos during incubation day 8 to incubation day 10. A 0.24 g lower residual yolk at the hatch of broiler embryos than for the layer embryos indicated that broiler embryos used more yolk and had a higher energy utilization and energy deposition in yolk-free body mass. Heat production of broiler embryos was higher than that of layer embryos from incubation day 12 to incubation day 18, but efficiency of converting egg energy used by embryos to form yolk-free body mass was similar. In conclusion, broiler and layer embryos have different embryonic development patterns, which affect energy utilization and embryonic heat production. However, the embryos are equal in efficiency of converting the energy used to yolk-free body mass.

Effect of eggshell temperature and oxygen concentration on survival rate and nutrient utilization in chicken embryos

Environmental conditions during incubation such as temperature and O(2) concentration affect embryo development that may be associated with modifications in nutrient partitioning. Additionally, prenatal conditions can affect postnatal nutrient utilization. Using broiler chicken embryos, we studied the effects of eggshell temperature (EST; 37.8 or 38.9 degrees C) and O(2) (17, 21, or 25%) applied from d 7 until 19 of incubation in a 2 x 3 factorial design. Effects of these factors on embryonic survival, development, and nutrient utilization were assessed in the pre- and posthatch period. High EST reduced yolk-free body mass compared with normal EST (36.1 vs. 37.7 g), possibly through reduced incubation duration (479 vs. 487 h) and lower efficiency of protein utilization for growth (83.6 vs. 86.8%). Increasing O(2) increased yolk-free body mass (from 35.7 to 38.3 g) at 12 h after emergence from the eggshell, but differences were larger between the low and normal O(2) than between the normal and high O(2). This might be due to the lower efficiency of nutrient utilization for growth at low O(2). However, the effects of O(2) that were found at 12 h were less pronounced at 48 h posthatch. When O(2) was shifted to 21% for all treatments at d 19 of incubation, embryos incubated at low O(2) used nutrients more efficiently than those incubated at normal or high O(2). An additional negative effect on survival and chick development occurred when embryos were exposed to a combination of high EST and low O(2). Possible explanations include reduced nutrient availability for hatching, decreased body development to fulfill the energy-demanding hatching process, and higher incidence of malpositions. In conclusion, EST and O(2) during incubation affect nutrient utilization for growth, which may explain differences in survival and development. Embryos raised under suboptimal environmental conditions in the prenatal period may develop adaptive mechanisms that still continue in the posthatch period.

Performance and energy metabolism in restrictively fed weanling pigs are not affected by feeding either fermented cereals or their end-products

To study the effects of feeding fermented cereals or just fermentation end-products on performance and energy metabolism, 18 restrictedly fed groups of eight pigs each were assigned to one of three dietary treatments: (i) a liquid control diet (C) containing 40% of a mixture of barley and wheat; or (ii) a liquid diet (F) containing 40% fermented barley and wheat; or (iii) a liquid diet as C with the addition of some important fermentation end-products (FP; organic acids and ethanol) in concentrations similar to those in the fermented F-diet. Energy and nitrogen balances, heat production, and performance traits were measured during two consecutive periods (days 1-5 and days 6-14). There was a considerable increase in average dry matter intake that tended (p = 0.06) to be higher in the FP-group than in the other groups. Apparent fecal digestibility of dry matter, ash, nitrogen and energy during period 2 were not affected (p > 0.1). Averaged over both periods, none of the energy metabolism parameters were affected by the diets (p > 0.1). However, there were diet × period interactions for metabolizable energy-intake (p = 0.07), energy retention (p < 0.05), the respiratory quotient (RQ; p < 0.01) and activity-related heat production (H(ACT,) p = 0.05). Additionally, there were some differences between the diets in the average hourly patterns in RQ and H(ACT). In conclusion, restricted feeding of either 40% fermented cereals nor their fermentation end-products affected performance and energy metabolism traits in weanling pigs. Nevertheless, lower postprandial activity-related heat production by pigs given the fermented cereals suggest a stimulating effect of fermented cereals on short term satiety that was not seen in pigs given fermentation end-products only.

Dietary energy source in dairy cows in early lactation: energy partitioning and milk composition

Metabolic problems related to negative energy balance suggest a role for the balance in supply of lipogenic and glucogenic nutrients. To test the effect of lipogenic and glucogenic nutrients on energy partitioning, energy balance and nitrogen balance of 16 lactating dairy cows were determined by indirect calorimetry in climate respiration chambers from wk 2 to 9 postpartum. Cows were fed a diet high in lipogenic nutrients or a diet high in glucogenic nutrients from wk 3 prepartum until wk 9 postpartum. Diets were isocaloric (net energy basis) and equal in intestinal digestible protein. There was no effect of diet on metabolizable energy intake and heat production. Cows fed the lipogenic diet partitioned more energy to milk than cows fed the glucogenic diet [1,175 +/- 18 vs. 1,073 +/- 12 kJ/(kg(0.75) x d)] and had a higher milk fat yield (1.89 +/- 0.02 vs. 1.67 +/- 0.03 kg/d). The increase in milk fat production was caused by an increase in C16:0, C18:0, and C18:1 in milk fat. No difference was found in energy retained as body protein, but energy mobilized from body fat tended to be higher in cows fed the lipogenic diet than in cows fed the glucogenic diet [190 +/- 23 vs. 113 +/- 26 kJ/(kg(0.75) x d)]. Overall, results demonstrate that energy partitioning between milk and body tissue can be altered by feeding isocaloric diets differing in lipogenic and glucogenic nutrient content.

Effects of eggshell temperature and oxygen concentration on embryo growth and metabolism during incubation

Embryo development and heat production (HP) were studied in eggs of similar size (60 to 65 g) that were incubated at normal (37.8 degrees C) or high (38.9 degrees C) eggshell temperature (EST) and exposed to low (17%), normal (21%), or high (25%) O(2) concentration from d 9 through 19. High EST initially increased HP, but gradually O(2) became more important for HP than EST. Finally,HP was highest for the combination of high EST with high O(2) and lowest for the combination of high EST with low O(2). High EST decreased hatch time, BW, yolk free BW, and relative heart weight. The EST had no effect on residual yolk weight, chick length, or relative liver weight. Increased O(2) increased yolk free BW and chick length and decreased residual yolk weight at hatch. No interactions between EST and O(2) were observed with regard to embryo development and hatchling characteristics. If embryo development is reflected by HP, it can be concluded that high EST primarily increased embryonic development until the second week of incubation. During the third week of incubation, O(2) had a greater effect in determining embryo development than EST.

Effects of increasing temperatures on physiological changes in pigs at different relative humidities

The effects of relative humidity (RH) and high ambient temperature (T) on physiological responses and animal performance were studied using 12 groups (10 gilts per group) in pens inside respiration chambers. The microclimate in the chamber was programmed so that T remained constant within a day. Each day, the T was increased by 2 degrees C from low (16 degrees C) to high (32 degrees C). Relative humidity was kept constant at 50, 65, or 80%. The pigs' average initial BW was 61.7 kg (58.0 to 65.5 kg), and their average ending BW was 70.2 kg (65.9 to 74.7 kg). Respiration rate (RR), evaporative water (EW), rectal temperature (RT), skin temperature (ST), voluntary feed intake (VFI), water-to-feed ratio (rW:F), heat production (HP), and ADG were analyzed. The animals had free access to feed and water. We determined the T above which certain animal variables started to change: the so-called inflection point temperature (IPt) or "upper critical temperature." The first indicator of reaction, RR, was in the range from 21.3 to 23.4 degrees C. Rectal temperature was a delayed indicator of heat stress tolerance, with IPt values ranging from 24.6 to 27.1 degrees C. For both these indicators the IPt was least at 80% RH (P < 0.05). Heat production and VFI were decreased above IPt of 22.9 and 25.5 degrees C, respectively (P < 0.001). For each degree Celsius above IPt, the VFI was decreased by 81, 99, and 106 g/(pig.d) in treatments 50, 65, and 80% RH, respectively. The ADG was greatest at 50% RH (P < 0.05). Ambient temperature strongly affects the pigs' physiological changes and performance, whereas RH has a relatively minor effect on heat stress in growing pigs; however, the combination of high T and high RH lowered the ADG in pigs. The upper critical temperature can be considered to be the IPt above which VFI decreased and RT then increased. Temperatures of the magnitude of both these IPt are regularly measured in commercial pig houses. We conclude that the upper critical temperatures for 60-kg, group-housed pigs fed ad libitum are between 21.3 and 22.4 degrees C for RR, between 22.9 and 25.5 degrees C for HP and VFI, and between 24.6 and 27.1 degrees C for RT. It is clear that different physiological and productive measurements of group-housed, growing-finishing pigs have different critical temperatures.

Energy Partitioning and Thyroid Hormone Levels During Salmonella enteritidis Infections in Pullets with High or Low Residual Feed Intake

This experiment was conducted to investigate whether feed efficiency, as measured by residual feed intake as a phenotypic trait, affects energy partitioning in pullets that have received Salmonella inoculation as an immune challenge. In each of 8 trials, energy partitioning was measured during 5 wk in 15-wk-old efficient (R-) and nonefficient (R+) pullets, which were housed per efficiency group in 2 identical climate respiration chambers. After 1 wk of adaptation, the pullets in 4 trials were orally inoculated with 10(8) cfu of Salmonella enteritidis; pullets in the remaining trials were not inoculated and served as controls. Heat production was calculated from continuous recordings of O(2) consumption and CO(2) production. Energy and N partitioning were recorded on a weekly basis. Blood samples for analyses on thyroid hormones were taken at 16, 17, and 19 wk of age. There were no interactions between efficiency type and Salmonella treatment or Salmonella treatment effects in energy partitioning, except for a short-term increase in heat production in inoculated pullets. Nonefficient pullets had higher gross energy and ME intake, higher estimated ME for maintenance, lower ME:gross energy ratio, and higher total heat production and nonactivity-related heat production compared with R- pullets. Triiodothyronine levels in R+ pullets were higher at 16 and 17 wk but were lower at 19 wk of age compared with R- pullets. Thyroxine levels were higher in R- at 16 wk and showed interactions between efficiency type and Salmonella treatment at 17 and 19 wk of age. Body weights and spleen weights did not differ between efficiency groups. Nonefficient pullets had higher heart, liver, and ovary weights and more large yellow follicles than R- pullets. There were no Salmonella effects on body and organ weights. We conclude that R+ pullets have a faster running energy metabolism and that they put more resources into organ development than R- pullets. Inoculation with Salmonella has a short-term effect on nonactivity-related heat production but does not affect energy partitioning, regardless of efficiency type.

Temperature and body weight affect fouling of pig pens1

Fouling of the solid lying area in pig housing is undesirable for reasons of animal welfare, animal health, environmental pollution, and labor costs. In this study the influence of temperature on the excreting and lying behavior of growing-finishing pigs of different BW (25, 45, 65, 85, or 105 kg) was studied. Ten groups of 5 pigs were placed in partially slatted pens (60% solid concrete, 40% metal-slatted) in climate respiration chambers. After an adaptation period, temperatures were raised daily for 9 d. Results showed that above certain inflection temperatures (IT; mean 22.6 degrees C, SE = 0.78) the number of excretions (relative to the total number of excretions) on the solid floor increased with temperature (mean increase 9.7%/ degrees C, SE = 1.41). Below the IT, the number of excretions on the solid floor was low and not influenced by temperature (mean 13.2%, SE = 3.5). On average, the IT for excretion on the solid floor decreased with increasing BW, from approximately 25 degrees C at 25 kg to 20 degrees C at 100 kg of BW (P < 0.05). Increasing temperature also affected the pattern and postural lying. The temperature at which a maximum number of pigs lay on the slatted floor (i.e., the IT for lying) decreased from approximately 27 degrees C at 25 kg to 23 degrees C at 100 kg of BW (P < 0.001). At increasing temperatures, pigs lay more on their sides and less against other pigs (P < 0.001). Temperature affects lying and excreting behavior of growing-finishing pigs in partially slatted pens. Above certain IT, pen fouling increases linearly with temperature. Inflection temperatures decrease at increasing BW.

Metabolic responses of chick embryos to short-term temperature fluctuations

Two experiments were carried out to study embryonic metabolic responses to short-term temperature fluctuations in order to explore the possibilities of using embryonic metabolic responses as a tool to control the incubation process. In the first experiment, eggshell temperature (ET) in the control group was kept constant at 37.8 degrees C, and embryos in the experimental group were exposed to varying ET within the range of 36.8 to 38.8 degrees C using ET steps of 0.2 degrees C and time steps of 3 h. This was repeated in 3 periods between 6.5 and 9.5 d, 10.5 and 13.5 d, and 14.5 and 17.5 d. In the studied ET range, heat production (HP) increased linearly at 4.9% per 1 degrees C ET. In the second experiment, a standard machine temperature (MT) was used for the control group, and eggs in the experimental group were exposed to low (MT - 0.3 degrees C) or high (MT + 0.3 degrees C) temperatures for 1 h of time at d 8, 9, and 11 to 16. When MT was decreased, CO2 production initially increased at 0.5% and decreased thereafter. When MT was increased, CO2 production initially decreased at 0.4% and increased thereafter. It was concluded that embryonic HP responded linearly with short-term ET changes in the studied ET range of 36.8 to 38.8 degrees C. Changes in CO2 concentration due to short-term MT changes could not be explained by embryonic HP only. It can be speculated that blood flow through the chorio-allantoic membrane changes with MT, affecting heat transfer and diffusion of CO2. A second, delayed response to MT changes was in accordance with the findings in Experiment 1. Within the studied temperature range it will be difficult to use embryonic metabolic responses as a tool to control the incubation process. Because HP is linearly related to ET as in the studied temperature range, other factors such as O2 availability or CO2 release may limit embryo development at higher ET. At this moment, research on the effects of gas exchange at different temperatures on embryo development and survival is lacking.

Effect of egg size on heat production and the transition of energy from egg to hatchling

An experiment was conducted to study the effect of egg size on embryo development, heat production, and energy partitioning between egg and hatchling. Small (56.1 +/- 0.12 g SEM) and large (70.0 +/- 0.11 g SEM) hatching eggs were incubated in climate respiration chambers, and eggshell temperature was maintained constant at 37.8 degrees C in both egg weight classes by adjusting machine temperature. Dry matter, ash, protein, and fat contents were determined in albumen, yolk, yolk-free body (YFB), and residual yolk (RY), and carbohydrate contents and caloric values were calculated. To achieve a constant eggshell temperature, machine temperature needed to be set lower from d 15 onward, coinciding with increased heat production in large eggs compared with small eggs. Selective nutrient uptake resulted in higher fat content and lower protein content in RY in chicks that hatched from small eggs compared with large eggs. The respiration quotient in small and large eggs was the same, and embryos in small and large eggs were equally efficient in the transfer of energy from egg to YFB. The surplus availability of nutrients in large eggs was therefore held responsible for the absolute and relative higher weight of RY in chicks that hatched from large eggs compared with small eggs.

Energy metabolism in young pigs as affected by establishment of new groups prior to transport

Energy metabolism was studied in 9-week-old-pigs as affected by mixing just before transport. In each of three trials, two groups of 20 pigs (two litters of 10) were randomly assigned to one of two treatments: control and mixing. Each group was housed in one of two climatic chambers with each subgroup in one of two pens. In each trial, the two litters within the mixing treatment were mixed, just before transport, at the start of a 2-week experimental period. In the control treatment, the social structure of both litters in each trial was not altered. In both treatments, large alterations of energy partitioning from week 1 to week 2, are probably signs of recovering from transportation and/or adaptation to new feeding and housing conditions. Mixing just before transport did not change total energy metabolism but only increased nonactivity-related heat production by 3.1% for the total experimental period. Most likely, long-term performance is also not affected negatively by mixing. Animals seem to be able to change energy expenditure on activity when more energy is required for other physiological processes. This symptom of possible reallocation of energy between different vital live processes (e.g. behavior, protein turn-over) might be one of the first indications of an impaired well-being.

Backtest type and housing condition of pigs influence energy metabolism1

The behavioral response of piglets in a backtest early in life seems indicative of their coping strategy at a later age. Coping characteristics may depend on the interaction between backtest classification and housing conditions. We studied whether growth rate and partitioning of energy in adult gilts were related to response in the backtest early in life, and to housing in groups or individual stalls. During the suckling period, female piglets were subjected to the backtest. Each piglet was restrained on its back for 1 min, and the number of escape attempts was scored. Thirty-six high-resisting gilts and 36 low-resisting gilts were selected. After weaning, pigs were housed in 12 groups of six (three high-resisting and three low-resisting). From 7 mo of age onward, 36 gilts out of six groups were housed in individual stalls, whereas the other gilts remained group housed. At 13 mo of age, gilts were housed in clusters of three (three high-resisting or three low-resisting) for an experimental period of 7 d in climatic respiration chambers. Group-housed gilts were loose housed, and stall-housed gilts were housed in stalls within the chamber. Despite the fact that high-resisting and low-resisting gilts did not differ (P = 0.269) in initial BW, low-resisting gilts showed a higher (P = 0.039) ADG during the experimental period in association with a higher (P = 0.043) energy metabolizability. This suggests that, in line with the theory on coping strategies, high-resisting gilts may have more difficulties in adapting to a change in environment, (i.e., the change from home pen to climatic chamber). Group- and stall-housed gilts differed (P = 0.001) in initial BW, with group-housed gilts being heavier. During the experimental period, stall-housed gilts showed lower energy metabolizability (P = 0.001), lower energy retention (P = 0.001), and a higher energy requirement for maintenance (P = 0.001) due to a higher activity-related heat production (P = 0.001). This finding suggests that stall housing might have a negative influence on performance and partitioning of energy when animals are adapting to a change in their environment.

Effects of cold stress on immune responses and body weight of chicken lines divergently selected for antibody responses to sheep red blood cells

Effects of cold stress (CS) on the immune system of chicken lines divergently selected for high (H line) and low (L line) antibody responses to SRBC next to a randombred control (C) line were studied. Three- to four-week-old growing chicks of the three lines were feed-restricted at 80% ad libitum and subjected to CS at 10 degrees C continuously for 7, 5, 3, 1, or 0 d prior to immunization with keyhole limpet hemocyanin (KLH). Specific and natural antibodies were measured in the three chicken lines subjected to or not subjected to various durations of CS prior to immunization. In addition to antibodies we also measured in vitro lymphocyte proliferation as a measure of cell-mediated immunity (CMI), zymosan-induced reactive oxygen intermediates (ROI) production as a measure of phagocytosis, and BW gain as a measure of production trait. In general, significantly higher antibody responses to KLH and natural antigens were found in the H line as compared to the other two lines. Specific antibody responses to KLH were not significantly affected by CS, but an acute transient increase in natural antibody titers to ovalbumin was found in H line birds subjected to 1 d of CS, which was not found in C or L line birds. On the other hand, an acute significant increase in natural antibody titers to lipopolysaccharide (LPS) was found in C and L line birds subjected to 1 d CS but not in H line birds. Cold stress enhanced the ROI production. In addition, 7 d of CS significantly enhanced cellular immunity in vitro, but no significant line effects with respect to cellular immunity were found. BW gain was negatively affected by CS, especially when CS was applied for longer periods. We concluded that birds responded immediately to CS with enhanced innate (phagocyte and natural antibody) immunity, irrespective of genetic background. When CS is prolonged, the cellular adaptive immune response is affected also. Although reallocation of energy was not measured, our data suggested that under limited conditions (e.g., restricted feeding) with simultaneous stress (e.g., CS), growth and cellular immunity were more sensitive than thermoregulation and humoral immunity. With respect to vital life traits, thermoregulation may have first priority followed by adaptive cellular immunity, humoral immunity, and BW gain. The relationships between immune responses and adaptation to stress are discussed.

Dietary betaine supplementation affects energy metabolism of pigs

The effect of dietary betaine supplementation on energy partitioning in growing pigs under energy-restricted dietary conditions was assessed. The effect of betaine on the adaptation in energy metabolism of pigs over time after a change in diet and housing also was studied. Six groups of 14 group-housed barrows were assigned to one of two experimental diets: control or betaine-supplemented (0 or 1.29 g/kg of feed). Diets were corn- and soybean meal-based and were formulated to be limiting in energy content but sufficient in amino acids. The experiment comprised a 3-wk adaptation and a 3-wk experimental period. At the start of the experimental period, initial BW was 46 kg, each group of pigs was housed in a climate-controlled respiration chamber, and all pigs were subjected to a change in diet. During the experimental period, diets were diluted with 10% oat hulls. Pigs were fed at 2.5 times the energy requirements for maintenance, and during the experimental period, heat production, energy, and nitrogen balances were measured weekly. Metabolizibility of energy did not differ (P > 0.10) between diets. Averaged over the experimental period, betaine reduced heat production (P < 0.05) and energy requirements for maintenance (P < 0.10) and consequently increased energy retention (P < 0.10). Moreover, the difference in heat production between diets increased with time (P < 0.05). Similarly, the effect of betaine on the energy requirements for maintenance changed with time (P < 0.05). Maintenance requirements were similar in wk 1 and were decreased by betaine supplementation by 5.5% during wk 3 (477 vs. 452 kJ/[kg(0.75) x d]). Results of this study show that dietary betaine supplementation affects energy partitioning by growing pigs. However, based on the observed time-related changes in energy partitioning, it was concluded that dietary betaine supplementation did not influence adaptation by pigs to a change in housing and diet.

Effects of two different dietary fermentable carbohydrates on activity and heat production in group-housed growing pigs

The effects of two sources of dietary fiber (DF) on behavior and heat production (HP) in group-housed growing pigs were studied. Twenty clusters of 14 barrows (50 kg) were fed one of 10 diets. Diets differed mainly in type and content of fermentable DF (fDF) and in content of digestible starch. Five diets contained solvent-extracted coconut meal (SECM) and five diets contained soybean hulls (SBH) as the main fDF source. On an as-fed basis, pigs received 3.5, 13.2, 23.0, 32.7, or 42.4 g x kg(-0.75) x d(-1) of SECM or SBH. A total of 280 crossbred growing pigs were used, divided into clusters of 14 pigs each. Pigs were group-housed and fed at 2.5 times the assumed maintenance energy requirements. All clusters were fed similar amounts of NE, ileal-digestible protein and amino acids, vitamins, and minerals. Consequently, DMI differed among diets because NE content decreased with increasing DF content. After a 32-d preliminary period, HP was measured per cluster during a 7-d experimental period in environmentally controlled respiration chambers. Behavior of the pigs was recorded using time-lapse video recordings during two different days within the experimental period. Intake of digestible starch and fDF was different (P < 0.001) among diets, whereas intake of digestible CP was similar among diets. On average, pigs spent 153 min standing, 42 min sitting, 202 min lying on their chest, and 1,043 min lying on their flanks each day. Pigs fed SECM diets spent, on average, less time (P < 0.05) lying on their chest than pigs fed SBH diets. Total time spent on physical activity (i.e., standing plus sitting, 195 min/d) was not affected by diet. Total HP and resting HP were affected by diet and were on average lower (P < 0.01) for pigs fed SECM diets than for pigs fed SBH diets. Activity-related heat production (AHP) averaged 65 kJ x kg(-0.75) x d(-1) and was not affected by diet. There was a linear relationship (P < 0.001) between fDF intake and HP, but there was no relationship between fDF intake and AHP. During different parts of the day, fDF intake also affected HP. The saving effect of physical activity on the NE values of fDF from SECM and SBH were 0.56 and 0.84 kJ/g of fDF intake, respectively. Neither of these saving effects was significantly different from zero. We conclude that fDF from SECM and SBH did not affect energy expended on physical activity by growing pigs, and that the NE value of fDF from SECM and SBH was not affected by changes in physical activity.

Effects of dietary fermentable carbohydrates on behavior and heat production in group-housed sows

The effects of dietary nonstarch polysaccharides (NSP) on behavior and heat production in group-housed sows were studied. Twelve groups of six nonpregnant sows were fed one of four experimental diets that were similar in composition except for starch and NSP contents. Exchanging sugar beet pulp silage (SBPS) for tapioca created the difference in dietary starch and NSP ratio. On a dry matter (DM) basis, diets contained 0, 10, 20, or 30% SBPS. Sows were group-housed. Intake of fermentable NSP (fNSP) for diets containing 0, 10, 20, or 30% SBPS averaged 7.06, 9.18, 11.61, and 13.73 g x kg(-0.75) d(-1), respectively. Sows were fed, once a day at 0800. Dry matter intake for diets containing 0, 10, 20, or 30% SBPS, averaged 38.05, 38.38, 38.53, and 38.35 g x kg(-075) x d(-1), respectively, and ME intake averaged 523, 518, 514, and 493 kJ x kg(-0.75) x d(-1), respectively. On average, sows spent 177 min/d on physical activity, of which 8.8% was spent on eating. Time spent in physical activity was affected by diet (P = 0.005). Sows fed 0 or 10% SBPS spent more time on physical activity than sows fed 20 or 30% SBPS (P = 0.002). Energy cost of physical activity averaged 464 kJ x kg(-0.75) x d(-1) (standard estimated mean of 31) and was similar for diets (P = 0.679). Total heat production (HP) and activity-related heat production (AHP) were affected by diet (P < 0.05). Sows tended to be quieter when fNSP intake increased (P = 0.063). The effect of fNSP intake on HP and AHP was not constant during the day. During the night period, fNSP intake did not affect HP and AHP (P > 0.10). During the day period, increased fNSP intake decreased HP (P = 0.006) and tended to decrease AHP (P = 0.062). During eating, increased fNSP intake increased HP (P = 0.012) and tended to increase AHP (P = 0.074). Despite similar DMI, sows fed 0 or 10% SBPS spent less time eating than sows fed 20 or 30% SBPS (P = 0.009). Feed consumption rate was higher (P = 0.003) in groups fed 0 or 10% SBPS than in groups fed 20 or 30% SBPS. Feed consumption rate decreased by 0.19 g DM x kg(-0.75). min(-1) (P = 0.003) for each gram of fNSP intake. The energy saving effect of physical activity on the NE value of fNSP from SBPS ranged between 2.3 and 3.7 kJ/g of fNSP intake. In conclusion, intake of fNSP from SBPS affected energy expenditure for physical activity (P = 0.063); however, this effect was not constant during the day.

Increased fat deposition after repeated immunization in growing chickens

We investigated the effects of sequential immunizations with seven different protein antigens (bovine gamma-globulin, keyhole limpet hemocyanin, rabbit gamma-globulin, tetanus toxoid, SRBC, human serum albumin, and BSA) on metabolic parameters (growth, food uptake, total heat production, metabolizability, energy retention as fat, and energy retention as protein) and antibody responses to these antigens in growing layer chickens. Energy and immune parameters of repeatedly immunized birds were compared with control birds in climate-respiration chambers in three trials. The last antigen (BSA) was given to both groups. Energy retention as fat was significantly higher in the repeatedly immunized group (P < 0.05). Antibody titers directed to BSA were similar for the repeatedly immunized groups and the control group. In addition, the separate antibody responses of the repeatedly immunized group to the administered antigens were compared with the antibody response of a control group receiving only a single antigen at the same age. With respect to several antigens, differences between groups were found. In the repeatedly immunized group, higher Day 0 (base line) titers were found to new antigens, introduced especially during the second half of the experiment. In these birds, significantly lower increases of antibody titers to some, but not all, antigens were found as compared to birds that were immunized only with the same antigen. It was concluded that repeated activation of the humoral immune response in growing layer chickens stimulated fat deposition but had little effect on other metabolic parameters. Repeated immunization had little effect on the immune response to separate antigens in the present experiments.

A prolonged photoperiod improves feed intake and energy metabolism of weanling pigs

In a 2-wk experiment, the effect of photoperiod on performance and energy metabolism of newly weaned pigs was studied. Forty 4-wk-old crossbred weanling barrows weighing 8.0 kg (SE = 0.13) were assigned to one of eight groups (five pigs per group) based on BW and litter. Groups were allotted to one of two lighting schedules: 8 h light:16 h darkness or 23 h light:1 h darkness. Each group was housed in a climate respiration chamber. Piglets had ad libitum access to feed and water. Energy and nitrogen balances, heat production, ADFI, and ADG were measured weekly. Heat production, energy metabolism, and performance were unaffected (P > 0.10) by photoperiod during wk 1. However, in the 2nd wk ADFI (418 vs 302 g/d) and ADG (381 vs 240 g/d) were higher (P < 0.05 and P = 0.05, respectively) for pigs on the 23:1 h lighting schedule than for those on the 8:16 h schedule. Furthermore, heat production (P < 0.10), total energy retention, and energy retained as protein and as fat were higher (P < 0.05) during wk 2 in pigs on the 23:1 h lighting schedule (8, 125, 41, and 350%, respectively) than in those on the 8:16 h schedule. Moreover, metabolizability of energy tended to be higher (P < 0.10) and energy requirements for maintenance were lower (P < 0.05) during wk 2 for pigs on the 23:1 h schedule compared with those on the 8:16 h schedule (P < 0.10). In conclusion, exposing pigs to a longer period of light after weaning stimulated ADFI and ADG. In addition to the feed intake, the high ADG is due to an improved metabolizability of energy and a reduced energy requirement for maintenance. This study suggests that lighting schedule can be used as a tool to stimulate feed intake after weaning.