Relationship between hatchling length and weight on later productive performance in broilers

Hatchling length and weight are used as tools to measure hatchling quality. However, the relationship between these parameters and later performance are not well known. This review evaluates the relationship between hatchling length or weight and slaughter weight, breast meat yield and feed conversion ratio (FCR) in both male and female broilers. Datasets from two trials were compared. In the first, hatchling length and weight of 100 male and 100 female broilers were measured and body weight and breast meat yield were determined at 38 days of age. In experiment 2, hatchling length of 187 female and 230 male broilers was measured and body weight was determined at 21 and 42 days of age. Feed intake was determined between 21 and 42 days of age. In both experiments, male broilers showed a positive relationship between hatchling length and slaughter weight or breast meat yield, but no relationship was found with hatchling weight. The relationship between hatchling length and performance in female broilers differed between the two experiments. In female broilers, a negative relationship between hatchling weight and breast meat yield was found. No relationship between hatchling length and FCR in both male and female broilers was found. From this limited dataset, it can be concluded that hatchling length seems to be a better parameter to predict subsequent chick performance, excluding FCR, than hatchling weight, but gender needs to be taken into accoun

The chicken embryo and its micro environment during egg storage and early incubation

When egg storage periods are prolonged (>7 days), hatchability and chick quality declines. The reason for this decline has been investigated, but is still not completely understood. At oviposition the developmental stage of the chicken embryo varies and so do the total number of viable cells. During storage, changes can occur in the embryo. Embryo viability at the end of storage seems to be dependent on the number of viable cells and the developmental stage of the embryo at oviposition. When the hypoblast is completely formed (during the quiescent developmental stage), the embryo seems to be more able to endure prolonged storage periods than embryos that are less or more advanced. During storage, changes also occur in egg characteristics such as albumen viscosity, albumen pH and yolk pH. There appears to be an interaction between albumen pH and embryo viability during early incubation and perhaps also during storage. An albumen pH of 8.2 seems to be optimal for embryo development. Albumen pH may influence embryo viability, but embryo viability may in turn, affect albumen pH. It has been hypothesised that an embryo in which the hypoblast is completely formed is better able to provide an effective barrier between the internal embryo and the exterior (yolk and albumen) and/or is better able to produce sufficient amount of carbon dioxide, which will reduce the pH level in the micro environment of the embryo to the optimal pH of 8.2. It appears that, to maintain hatchability and chick quality after prolonged storage periods, embryonic development should be advanced to the stage in which the hypoblast is completely formed or the atmosphere during storage and early incubation should be altered in such a way that albumen pH is maintained at the optimal level of 8.2

Meeting embryonic requirements of broilers throughout incubation: a review

During incubation of chicken embryos, environmental conditions, such as temperature, relative humidity, and CO2 concentration, must be controlled to meet embryonic requirements that change during the different phases of embryonic development. In the current review, the effects of embryo temperature, egg weight loss, and CO2 concentration on hatchability, hatchling quality, and subsequent performance are discussed from an embryonic point of view. In addition, new insights related to the incubation process are described. Several studies have shown that a constant eggshell temperature (EST) of 37.5 to 38.0 degrees C throughout incubation results in the highest hatchability, hatchling quality, and subsequent performance. Egg weight loss must be between 6.5 and 14.0% of the initial egg weight, to obtain an adequate air cell size before the embryo internally pips. An increased CO2 concentration during the developmental phase of incubation (first 10 days) can accelerate embryonic development and hatchability, but the physiological mechanisms of this acceleration are not completely understood. Effects of ar increased CO2 concentration during late incubation also need further investigation. The preincubation warming profile, thermal manipulation, and in ovo feeding are new insights related to the incubation process and show that the optimal situation for the embryo during incubation highly depends on the conditions of the eggs before (storage duration) and during incubation (environmental conditions) and on the conditions of the chickens after hatching (environmental temperature)

Involvement of the hypothalamic-pituitary-thyroid axis and its interaction with the hypothalamic-pituitary-adrenal axis in the ontogeny of avian thermoregulation: a review

The emergence of thermoregulation in avian species is a complex matter in which neural as well as hormonal processes are involved. In a previous paper, the neural aspects of primary avian thermoregulation were discussed. In this paper the role of the hypothalamus-pituitary-thyroid axis (HPT-axis) and the hypothalamus-pituitary-adrenal axis (HPA-axis) in the ontogeny of avian thermoregulation is evaluated. The regulatory mechanisms and different important hormones of both axes, which have stimulatory or inhibitory effects, are discussed. Because the onset of functionality of the thermoregulatory system is of great interest, the ontogeny and functionality of the hormonal axes are clarified. There is a great difference between precocial and altricial birds in hormonal events as well as in neural processes which are involved in the emergence of thermoregulation. In precocial avian species the HPT-axis becomes functional during the mid- to late embryonic period while the same axis only becomes fully functional during the first week post-hatch in altricial avian species. As early as the sixties, the emergence of homeothermy in chickens was investigated. It was concluded that the thyroid gland plays an important role in the thermoregulatory mechanisms of newly hatched chicks. More recent studies however were not able to show any direct effect of the thyroid hormones on the thermoregulation of day-old chicks, although blocking the conversion of T4 to T3 caused a decrease in body temperature in young chicks. Thyrotropin releasing hormone (TRH) is known to act in thermoregulation in mammals and several authors have found an effect of TRH on the metabolism of young and older chicks. However, the exact mechanism still remains unclear. Because the HPT- and the HPA-axis show close relationships, the role of the HPA-axis in the ontogeny of thermoregulation is also taken into consideration in this review. In mammals as well as in birds, corticotropin releasing hormone (CRH) is involved in the primary thermoregulation. We conclude that the HPT-axis has an important role in the ontogeny of avian thermoregulation. The exact role of the HPA-axis remains largely unclear although at least CRH is definitely of some importance

Energy partitioning and reproduction in primiparous sows : effects of dietary energy source

IntroductionAs a result of extensive changes in pig husbandry in the last 50 years, nutritional requirements of especially lactating sows nowadays differ strongly from those of sows in the past. Although diets are optimized to meet the requirements, sows still loose body reserves during lactation. Especially in primiparous sows, losses of body reserves during lactation are severe. These sows have not reached their mature body weight and therefore need nutrients for body development. However, due to a limited feed intake capacity, lactating primiparous sows mobilize body fat and protein to meet their requirements for maintenance and milk production.In general, these losses of body reserves result in impaired reproductive performance after weaning. The number of sows that remain anestrous after weaning is considerable and in sows that show estrus, weaning-to-estrus interval (WEI) is prolonged, ovulation rate seems decreased and embryonal mortality is increased.Therefore, nutrition is an important factor for optimal reproductive performance, especially in primiparous sows. An intermediate between nutrition and reproduction is the hormone insulin. Insulin is associated with the pulse frequency of luteinizing hormone (LH), WEI, ovulation rate, and farrowing rate. Feeding level, exogenous insulin injections, and diet composition can affect plasma insulin concentration. Effects of dietary energy source on plasma insulin concentration and its relationships with reproductive performance are hardly investigated.This study was conducted in primiparous sows to investigate: 1) effects of two specific dietary energy sources (fat: less insulin-stimulating vs starch: more insulin- stimulating) fed during different parts of the reproduction cycle, on reproductive traits, and 2) whether effects of these dietary energy sources on reproduction are dependent on the metabolic status during lactation (induced by feeding level).Dietary energy sources and plasma insulin concentration (Experiment 1)To investigate effects of dietary manipulated plasma insulin concentration on reproductive performance, firstly diets had to be composed that differ in insulin stimulation. Therefore, an experiment was conducted in cyclic gilts in which three diets, differing in major dietary energy sources, were investigated in their ability to stimulate plasma insulin secretion (Chapter 1). The studied major dietary energy sources were tallow, maize starch, and maize starch plus dextrose. The diet with tallow gave only a slight postprandial increase in plasma insulin level. The maize starch diet resulted in a higher postprandial insulin concentration, but two hours after feeding the plasma insulin concentrations were not different between the diet with tallow and with maize starch. The diet with maize starch plus dextrose resulted in the highest postprandial insulin levels and remained at a higher level during approximately 4.5 h after feeding. Preprandial insulin concentrations did not differ between diets.Design Experiment 2Because the diet with tallow (fat) and the diet with maize starch plus dextrose (starch) gave the largest contrast in plasma insulin concentration, these two diets were used in a large experiment with lactating primiparous sows. Sows received either the fat- or starch-rich diet from farrowing up to d 35 of the subsequent pregnancy. During lactation, sows were fed either a high (44 MJ NE/d; 1050 g CP/d) or a low (33 MJ NE/d; 790 g CP/d) feeding level. This was done to study, in addition to the main effects, the interactions between dietary energy source and feeding level on energy partitioning and reproduction. Within each feeding level, diets were fed to be isocaloric and isonitrogenous. After weaning, all sows remained at the same experimental diet, but all received the same amount of energy and protein (from weaning to estrus: 31 MJ NE/d; 740 g CP/d; from breeding to slaughter: 17.5 MJ NE/d; 420 g CP/d).During lactation, energy and nitrogen balance were determined and blood samples were collected to analyze insulin and LH profiles. After weaning (day 22 after farrowing), additional blood samples were taken to analyze periovulatory profiles of estradiol, LH, and progesterone. Sows were inseminated each day of standing estrus and slaughtered on d 35 of pregnancy. Results obtained from this experiment are described in Chapter 2 to 5.Dietary energy source and energy partitioning (Experiment 2)Effects of dietary energy source and feeding level on milk production, milk composition, piglet body composition, and energy partitioning of lactating primiparous sows are described in Chapter 2. At the low feeding level no differences between the two dietary energy sources were observed for milk composition, body composition of the piglets, or energy and nitrogen balance of the sow. At the high feeding level, however, the fat-rich diet resulted in milk with a higher fat concentration and in piglets with a higher body fat concentration compared with the starch-rich diet. This resulted in an interaction between dietary energy source and feeding level for energy balance of the sows. The energy balance of sows fed the low feeding level and of sows fed the fat-rich diet at the high feeding level were all similar, but the energy balance of sows fed the starch-rich diet at the high feeding level was less negative. These results suggest that extra fat in the diet enhances milk fat output, whereas extra starch is used for both milk production and prevention of severe body reserve losses of the sow.Dietary energy source, feeding level, and reproductive traits (Experiment 2)Whether the treatments affected plasma insulin profiles and reproductive traits during and after lactation is described in Chapter 3 and 4. Plasma insulin concentration was higher in sows fed the starch-rich diet than in sows fed the fat-rich diet during lactation. LH pulse frequency during lactation tended to be lower in sows fed the fat-rich diet compared to those fed the starch-rich diet. At the high feeding level, no effect of dietary energy source on WEI was found. However, at the low feeding level, the fat-diet resulted in a 22 h longer WEI compared with the starch-rich diet. Dietary energy source did not affect other reproductive traits.Feeding level did not affect plasma insulin profiles during lactation. Sows fed the high feeding level during lactation had a higher LH pulse frequency during and after lactation, a lower risk to remain anestrous after weaning, and a higher ovulation rate compared with sows fed the low feeding level. Periovulatory profiles of estradiol, LH, and progesterone hardly differed between treatments. No differences between treatments were observed for the number of embryos, uterine-, and placental development.Plasma insulin concentrations during lactation were never related with the determined reproductive traits. Furthermore, no relationships were found between energy- or nitrogen balance and reproductive characteristics.Based on the results obtained from experiment 2, it can be concluded that dietary energy source during lactation affects plasma insulin concentration but has minor effects on reproductive performance of primiparous sows. A reduction of 25% in lactational feed intake seems to have more impact on reproductive traits.Overall analyses, regardless of treatments, showed that the relationship between the number of LH pulses on the day of weaning and the WEI was best explained by a linear-plateau model. An increase from two to seven LH pulses per 12 h resulted in a linear decrease in WEI, whereas more than 7 pulses did not shorten the WEI further. Furthermore, it was demonstrated that the mean plasma progesterone concentration in early pregnancy was positively related with the percentage of embryo survival, especially in progressing pregnancy (from 170 h after the LH surge onwards).Dietary energy source and reproductive performance (Experiment 3).In the experiment described above (Chapter 2 to 4), sows were fed either the fat- or starch-rich diet from parturition until d 35 of subsequent pregnancy It is therefore, impossible to distinguish effects of dietary energy source fed during the lactation period, the WEI, or the early pregnancy, on reproduction. Effects found during pregnancy may be a result of changes during WEI or even lactation. Therefore, another experiment was conducted in which primiparous sows were fed either the fat- or starch-rich diet during the weaning-to-ovulation interval or during early pregnancy (until d 35). The results obtained from this experiment are described in Chapter 6. Sows fed the fat-rich diet before ovulation had a higher risk to maintain anestrous after weaning than sows fed the starch-rich diet. No effect of dietary energy source fed either before ovulation or during early pregnancy was found on uterine, placental, and embryonic traits.IGF-1 and reproductive performance (Experiment 2 and 3)Because plasma insulin concentration did not show relationships with reproductive traits (Chapter 3 and 4), additional analyses were performed to determine plasma IGF-1 (insulin-like growth factor-I) concentration during and after lactation, and its relationships with reproductive characteristics. In literature, IGF-1, together with insulin, is often posited as an intermediate between nutrition and reproduction in the pig. Results of these analyses are described in Chapter 5. Plasma IGF-1 concentration was higher in sows fed the high feeding level during lactation and also in sows fed the starch-rich diet. Furthermore, IGF-1 concentrations on d 21 of lactation and on d 22 (weaning) were positively related with the LH pulse frequency on d 22 and the height of the preovulatory LH surge. Finally, IGF-1 concentration in sows with a low body weight at farrowing and severe lactational body weight loss was decreased compared to heavier sows at farrowing or sows with less lactational body weight loss.Conclusions and implicationsThe major question to be answered in the present study was whether dietary energy source affects plasma insulin concentrations and reproductive performance of primiparous sows. Based on the results obtained from the three experiments, it can be concluded that fat-rich diets fed during lactation depress the secretion of insulin compared to starch-rich diets. The LH secretion by the pituitary during lactation tended to be decreased in sows fed the fat-rich diet, possibly explaining the finding that the return to estrus was delayed in these sows. However, this lower LH pulsatility and delayed return to estrus were not related to plasma insulin concentration. Dietary energy source does not seem to affect reproductive traits on the uterus level.The second question to be answered was whether effects of dietary energy source on reproductive performance are dependent on the metabolic status of sows during lactation. In the present study, no interaction between dietary energy source and metabolic status on reproductive traits was found, even though the energy balance of the lactating sows was affected by dietary energy source.Based on these results, the use of fat-rich diets for primiparous sows, and probably also for multiparous sows, needs to be critically evaluated. Based on the metabolic and reproductive point of view, starch-rich diets seem to be more beneficial for sows than fat-rich diets. Effects of fat-rich diets on litter performance after weaning need to be investigated further.</p

Effects of fermentable starch and straw-enriched housing on energy partitioning of growing pigs

Both dietary fermentable carbohydrates and the availability of straw bedding potentially affect activity patterns and energy utilisation in pigs. The present study aimed to investigate the combined effects of straw bedding and fermentable carbohydrates (native potato starch) on energy partitioning in growing pigs. In a 2 × 2 factorial arrangement, 16 groups of 12 pigs (approximately 25 kg) were assigned to either barren housing or housing on straw bedding, and to native or pregelatinised potato starch included in the diet. Pigs were fed at approximately 2.5 times maintenance. Nitrogen and energy balances were measured per group during a 7-day experimental period, which was preceded by a 30-day adaptation period. Heat production and physical activity were measured during 9-min intervals. The availability of straw bedding increased both metabolisable energy (ME) intake and total heat production (P <0.001). Housing conditions did not affect total energy retention, but pigs on straw bedding retained more energy as protein (P <0.01) and less as fat (P <0.05) than barren-housed pigs. Average daily gain (P <0.001), ME intake (P <0.001) and energy retention (P <0.01) were lower in pigs on the native potato starch diet compared to those on the pregelatinised potato starch diet. Pigs on the pregelatinised potato starch diet showed larger fluctuations in heat production and respiration quotient over the 24-h cycle than pigs on the native potato starch diet, and a higher activity-related energy expenditure. The effect of dietary starch type on activity-related heat production depended, however, on housing type (P <0.05). In barren housing, activity-related heat production was less affected by starch type (16.1% and 13.7% of total heat production on the pregelatinised and native potato starch diet, respectively) than in straw-enriched housing (21.1% and 15.0% of the total heat production on the pregelatinised and native potato starch diet, respectively). In conclusion, the present study shows that the availability both of straw bedding and of dietary starch type, fermentable or digestible, affects energy utilisation and physical activity of pigs. The effects of housing condition on protein and fat deposition suggest that environmental enrichment with long straw may result in leaner pigs. The lower energy expenditure on the physical activity of pigs on the native potato starch diet, which was the most obvious in straw-housed pigs, likely reflects a decrease in foraging behaviour related to a more gradual supply of energy from fermentation processes

Effecten van eenvoudige koolhydraten en fermenteerbare koolhydraten op de binnentoom variatie bij varkens

2 proeven werden uitgevoerd. Het doel van de 1e was nader inzicht te krijgen in het mechanisme dat ten grondslag ligt aan de relatie tussen insuline-stimulerend voer (dextrose+lactose) tijdens het interval spenenovulatie, follikelontwikkeling in de laatste dagen voor inseminatie en (variatie in) ontwikkeling van embryo's tijdens de vroege dracht. Het doel van de 2e proef was om nader inzicht te krijgen in de directe effecten van de specifieke voercomponenten dextrose, lactose, sucrose en suikerbietenpulp (zowel apart als gecombineerd) op glucose, insuline en IGF-1 profielen in zeugen om zo diëten te vinden met de hoogste potentie om insuline en IGF-1 afgifte te stimuleren

Prototyping the Semantics of a DSL using ASF+SDF: Link to Formal Verification of DSL Models

A formal definition of the semantics of a domain-specific language (DSL) is a key prerequisite for the verification of the correctness of models specified using such a DSL and of transformations applied to these models. For this reason, we implemented a prototype of the semantics of a DSL for the specification of systems consisting of concurrent, communicating objects. Using this prototype, models specified in the DSL can be transformed to labeled transition systems (LTS). This approach of transforming models to LTSs allows us to apply existing tools for visualization and verification to models with little or no further effort. The prototype is implemented using the ASF+SDF Meta-Environment, an IDE for the algebraic specification language ASF+SDF, which offers efficient execution of the transformation as well as the ability to read models and produce LTSs without any additional pre or post processing.Comment: In Proceedings AMMSE 2011, arXiv:1106.596

Gevolgen van een moeilijke kippenjeugd

Kippengeluk wordt al bepaald in het ei. Een kuiken dat op de juiste temperatuur is uitgebroed is gezonder en waarschijnlijk ook minder angstig dan soortgenoten die het in het ei te heet of te koud hebben gehad. Ook de eerste levensweken van een kip blijken van grote invloed op de latere gezondheidstoestand van het die