Browsing by Author "Ciacciariello, Mariana."

Now showing 1 - 14 of 14

Breast meat yield in broilers affected by lighting and dietary energy levels in starter and finisher phases.
(2015) Smith, Giles Elliott.; Ciacciariello, Mariana.; Tyler, Nicola Claire.
The increased demand in poultry products has prompted researchers to investigate opportunities and methods which may streamline the production of valuable commodities. Two experiments were conducted in this study. Both experiments were conducted to determine whether breast meat yield (BMY) would be enhanced in broilers reared under short daylengths of 8 and 16 h if higher levels of dietary metabolisable energy (ME) were fed. In each experiment, 1000 as hatched broilers were reared in four light tight rooms, each room divided into two pens which were populated with 125 chicks in each. Within each room two levels of dietary ME were fed resulting in a 2 × 2 factorial experimental design with the main effects being daylength and dietary ME. The first experiment focused on the starter phase of 1 to 10 d. The dietary treatments consisted of a control starter ration formulated to represent the nutrient levels of a standard commercial ration and a treatment ration which was similar to the control ration however contained 15% higher ME. Live weight and performance parameters of body weight gain (BWG), feed intake (FI) and feed conversion ratio (FCR) were measured at 7 and 10 d. At 10d, three birds from each pen were randomly selected and slaughtered for body part analysis. Lighting and dietary treatment had no effect on live weight, BWG, FI and FCR at 7 or 10d. Body part analysis showed that BMY, thigh yield and drumstick yield were unaffected by lighting and dietary ME as main effects. A significant interaction between dietary ME and daylength occurred where BMY and thigh yield were reduced when broilers were fed a 15% higher ME diet and reared on 8 h daylengths. The second experiment focused on the finisher phase of 25 to 35d. Lighting treatments remained the same as the first experiment but dietary treatments differed slightly as the treatment diet contained only 10% higher ME than the control diet which was formulated to the nutrient levels of a standard broiler finisher. At 35 d performance parameters of live weight, BWG, FI and FCR were measured. It was observed that live weight and FI were reduced in broilers fed a diet containing 10% higher ME from 25 to 35d. At 35d, body part analysis from 3 broilers slaughtered from each pen revealed no significant differences in BMY, thigh yield and drumstick yield from dietary ME and daylength. Breast meat yield in broilers within the starter and finisher phase was not improved on short daylengths of 8 and 16 h through the addition of dietary ME in higher levels than that conventionally used.
The effect of crude protein intake on fertility in young and old male broiler breeders.
(2014) Graaf, Brendan.; Tyler, Nicola Claire.; Ciacciariello, Mariana.
Due to genetic selection and improvements in broiler growth traits there have been negative influences on fertility in broiler breeder parents. This is mainly related to excess body weight gain resulting in the inability to achieve successful cloacal contact during copulation and problems with the hierarchical formation of follicles in the ovary. Male broiler breeders are often fed a female ration which contains crude protein (CP) requirements for egg production, and may not be necessary for males. Protein is one of the most costly components of poultry feed, and overfeeding protein has a number of downsides. The impact of sub-fertile and unfertile males in the overall fertility of the flock could be large. Maximizing male fertility could ensure maximizing fertile egg production which would result in more broiler chicks without increasing the size of the breeding flock. The objective of this experiment was to investigate the effects of three different dietary CP intakes (96.8, 117 and 130 g CP/kg, low, medium and high respectively) on fertility in young and old male broiler breeders using some old and more recent fertility measures in an attempt to determine whether it would be justified to feed males a separate ration. Results showed that across all male ages no significant response in body weight (BW), sperm concentration and sperm mobility to dietary CP intake were seen. Although in the young males, birds on the high CP intake showed significantly (P<0.05) lower mean BWs than males on the low and medium CP intakes, and sperm mobility values were seen to be highest in birds receiving the medium CP intake across all male ages. The log number of inner perivitelline layer (IPVL) sperm holes was seen to increase with increasing CP intake (P<0.001) in males between 42 and 62 weeks of age (WOA) but showed no response in males from 27-41 WOA. The log number of IPVL sperm holes was seen to generally decrease with age in males from 27-60 WOA; however eggs collected two days postartificial insemination (PAI) had a similar log number of IPVL sperm holes, regardless of treatment, throughout the study. The mean number of IPVL sperm holes was seen to decrease as days PAI increased. There was a tendency for a superior response in fertility, predicted from IPVL sperm holes, from birds on the medium protein intake.
The effect of education on smallholder pig farmers' knowledge, practices and pig productivity in the Angónia District, Mozambique.
(2015) Alfredo, Zeiss Lacerda.; Ciacciariello, Mariana.; Mejer, Helena.; Tyler, Nicola Claire.
Smallholder pig production provides an important contribution for farmer livelihoods in many African developing countries. However, there are many constraints that limit pig performance and thus financial outcome. The present on-farm trial was carried out from June 2011 to September 2012 in four villages in the Angónia district, Tete province, Mozambique. The aim was to evaluate the effectiveness of pig health, housing, feeding and reproduction education of smallholders pig farmers on the knowledge uptake, changes in pig management practices and performance of sows and their offspring. All four villages were taught pig health and housing, but information on either feeding, reproduction or feeding and reproduction was also provided to each of three villages. The education was provided through an initial focussed group discussion followed by a collective and participatory training session. In addition, construction of a good quality pig pen was demonstrated in each village and throughout the study farmers received on-farm knowledge reinforcement. For evaluation of knowledge and practices, pig farmers (total across the villages: n=179) were tested using a semi-closed questionnaire and on-farm observation pre-education (baseline, month zero) and posteducation (month thirteen). Reproduction data from sows (n=125) and production data from their progeny (from birth until 8 months age, n=461) were collected from June 2011 to June 2012. Overall, 58% of the sows could be monitored to the end of the study. Overall high and significant proportions of farmers demonstrated knowledge uptake but the changes in practices were more modest except for pig pen quality, which improved substantially. The only significant change in pig productivity was an increase in the number of litters per sow in only one of the two villages taught reproduction. Unfortunately, this was countered by high piglet mortality so the number of weaned piglets was the same as in the other villages. It is concluded that, though education can induce substantial knowledge uptake by smallholder farmers, it is more difficult to change their practices. This was probably in part due to lack of resources, but overall with just a little change there is a potential for improving pig performance.
The effects of dietary crude protein on fertility of broiler breeder males.
(2010) Waltsleben, Stephanie Lisa von.; Tyler, Nicola Claire.; Ciacciariello, Mariana.
Fertility of Broiler Breeders (BBs) has been researched over many years with inconclusive findings. Genetic selection and improvements in growth traits have had negative effects on fertility of BB. One explanation is related to overweight birds, resulting in the inability of birds to copulate successfully, with no cloacal contact. The requirements of CP for egg production in BB females have been quantified, but there is less literature on how CP affects fertility in male BBs. The objective of this experiment was to investigate the effects of feeding BB males different dietary CP intakes (10.4, 12.4, 14.2, 17.8, 19.3 and 20.1 g CP/bird/day) on fertility in flocks with natural mating and in birds that were artificially inseminated (AI). Results showed that birds consuming 10.4 and 12.4 g CP/bird/day resulted in weight loss (between 24.9 and 23.6% and 26.5 and 22.4% below target BW) over the 29 weeks of the experimental period in both natural mating and individual pens respectively. Intakes of higher protein content (17.8- 20.1 g CP/bird/day) however resulted in BW gain over the experimental period. Hatch percentage across all CP intakes throughout the duration of the study was found to be high, ranging between 75- 100 and 80-95 % in AI and naturally mated birds respectively, and not affected by CP intakes. Similar results for predicted fertility using the methods published by Brillard & Antoine (1990) and Wishart (1997) were found; however Brillard & Antoine (1990) is more lenient requiring less outer perivitelline layer (OPVL) sperm/mm2 to pronounce an egg fertile. Improved fertility predictions could have been made by using examination of inner perivitelline layer (IVPL). There was a tendency for a superior response in predicted fertility from birds with a protein intake of 14.2 g CP/bird/day. This intake also least affected the BW of the male birds and thus 14.2 g CP/bird/day can be recommended for optimal BB male performance.
The effects of dietary lysine, crude protein, energy and feed allocation on broiler breeder hen performance.
(2013) Patel, Jamila.; Ciacciariello, Mariana.
This study was conducted to investigate the effects of varying levels of dietary lysine and feed allocation, on the performance of female broiler breeders. In trial 1, 900 Cobb breeders from 26 to 45 weeks of age were used. The first four treatments had a fixed level of lysine throughout the experimental period, with 1200, 1070, 930 and 800 mg Lysine/bird/day and the last two treatments had their levels of lysine changed every two weeks, with treatment five started off with 1200 mg lysine/bird/day followed by a gradual decrease up to 975 mg lysine/bird/day at 45 week old, while treatment six started with the lowest level of lysine, 800 mg/bird/day and at 45 week old the intake was 1025 mg/bird/day. The rations provided 1900KJ ME/ day, the birds received 160 g of feed/day. Dietary lysine did not affect body weight, egg production, or egg composition. There were no significant differences in age at 50%, or peak production. Birds receiving 1070 and 1025 mg lysine/bird.day had a slightly, but not significantly, higher production in the current study. Birds receiving 1200 mg lysine/bird.day had the highest body weight and the lowest egg production. In trial 2, 900 broiler breeder hens were used. Protein intake and feed allocation were changed for each treatment at 26, 38 and 50 weeks and ending at 60 weeks. Birds on T1 were fed a constant CP content (145 g protein/kg) but a decreasing feed allocation (175 to 145 g/d). Those on T2 had a constant feed allocation (160 g/d) and a decreasing CP (166 to 124 g/kg) while those on T3 had varying levels of protein (166, 124 and 166 g/kg) and feed allocation (160, 160, 145 g/d). Mean cumulative protein intakes were 5.2, 5.3 and 4.8 kg/bird and mean energy intakes were 417, 412 and 402 MJ/bird for T1, T2 and T3 respectively. Body weights differed significantly at the end of the trial (P<0.05) with T2 showing the highest weight gain. However, egg production, egg weight and egg output were not affected by treatment. These breeders did not benefit from the additional protein and energy provided in the first and second periods by T1 and T2 (vs. T3), nor did they benefit from the additional energy provided in the final ten weeks of production by T2.
Effects of essential oil, probiotic, palm kernel fatty acid distillate, optigut, or sunflower whole seeds as alternatives to antibiotic growth promoters on broiler performance.
(2019) Tshonaphi, Caswell Sifiso.; Ciacciariello, Mariana.
The increasing consumer and legislation pressure to phase out the antibiotic growth promoters (AGPs) in the broiler industry has prompted researchers to find suitable alternatives to AGPs that will improve broiler performance at levels comparable to AGPs. There were three trials that were conducted in the present study. The aim of the first trial was to evaluate the effects of supplementing broiler diets with Oligo essential (essential oil) or AGPs on growth performance and caecal Clostridium perfringens (C. perfringens) counts of broilers from 0 to 33 days of age, reared in a commercial farm. A total of ten broiler houses were used for the trial. Five houses were designated for broilers receiving feed supplemented with AGPs and other five houses for broilers receiving feed supplemented with Oligo Essential. The houses were used as experimental units. The control houses (1, 2, 3, 4, and 5) were paired with trial houses (7, 8, 9, 10, and 11). The chicks placed in paired houses had the same parent flock age, were placed on the same day and also slaughtered at the same age. A total of 300 000 day old broiler chicks (Cobb 500) of mixed sex were used in the trial and the stocking density per house was 22.10 birds/m2. In the period of 0 to 33 days of age, it was observed that the broilers that were fed diets supplemented with Oligo Essential had a significantly poorer feed conversion ratio (FCR) and higher feed intake (FI) when compared to broilers that were fed diets containing AGPs. However, no effect of dietary treatment was seen on the body weight (BW). The caecal C. perfringens counts at 9 and 30 days of age were unaffected by dietary treatment. In conclusion, supplementing broiler diets with Oligo Essential had negative effects on broiler performance in the present study. In the second trial, the objective was to determine the effects of Lactobacillus based probiotic or AGPs on broiler performance in a commercial farm. A total of six broiler houses were used for the trial. Three houses were designated for broilers receiving feed supplemented with AGPs and other three houses for broilers receiving feed without AGPs, but all the day-old chicks were sprayed with Lactobacillus based probiotic at the hatchery. The dosing volume was 10ml per 100 chicks. The houses were used as experimental units. The control houses (1, 2, and 3) were paired with trial houses (4, 5, and 6). The chicks placed in paired houses had the same parent flock age, were placed on the same day and also slaughtered at the same age. A total of 180 000 day old broiler chicks (Cobb 500) of mixed sex were used in the trial and the stocking density per house was 20.80 birds/m2. It was noted that there was no significant difference in BW, FCR, FI and mortality between the treatments at 33 days of age. Therefore, it was concluded that the Lactobacillus based probiotic demonstrated feasibility of being a substitute for AGPs as the broiler performance was comparable to broilers that received diets supplemented with AGPs. In the third trial, the objective was to investigate the effects of Optigut, palm kernel fatty acid distillate and sunflower whole seeds on broiler performance, organs weights, intestinal length, digesta pH and caecal microbial profile. A total of 3360 Cobb 500 day old broiler chicks were randomly distributed into 48 pens. There were six dietary treatments for the trial: (i) Negative control with no AGPs; (ii) Negative control supplemented with AGPs; (iii) Negative control supplemented with Palm kernel fatty acid distillate at 2.5%; (iv) Negative control supplemented with Optigut at 0.4% in the starter, 0.2% in the grower and 0.1% in the finisher; (v) Negative control supplemented with Sunflower whole seeds at 4.0%; (vi) Negative control supplemented with Palm kernel fatty acid distillate (2.5%) and Sunflower whole seeds (4.0%). It was observed that there was no significant treatment effect on broiler performance parameters, organs weights, intestinal length, digesta pH and caecal microbial profile at 35 days of age. The results of the study suggest that the trial was conducted in a hygienic environment, therefore, it was recommended to conduct challenge studies to further investigate the effects of these alternatives to AGPs.
The effects of maternal dietary lysine intake on broiler breeder offspring performance.
(2011) Khetani, Thamsanqa Lucky.; Ciacciariello, Mariana.; Tyler, Nicola Claire.
The aim of this study was to evaluate the effects of broiler maternal dietary lysine intake on progeny performance. Three experiments were conducted with chicks hatched from Cobb 500 breeders at 38, 48, and 60 weeks of age. Breeder hens received six dietary treatments (T1-T6) from 26 to 60 weeks of age, which allowed an intake of 800, 930, 1070, and 1200 mg lysine/bird/d (T1-T4) respectively. An intake of 800 mg/bird/d at 26 weeks was increased by 25 mg every two weeks to provide 1225 mg lysine/bird/d at 60 weeks (T5). An intake of 1200 mg/bird/d at 26 weeks was reduced by 25 mg every two weeks to supply 775 mg lysine/bird/d at 60 weeks (T6). A total of 320, 401, and 390 chicks were hatched from breeder hens at 38, 48, and 60 weeks of age respectively. Immediately after hatching, 270, 384, and 384 unsexed chicks from breeder hens at 38, 48 and 60 weeks of age respectively, were placed in an environmentally controlled room and randomly allocated (within a treatment) to single-tier cages (80 × 50 cm). Nine chicks from breeders at 38 weeks of age and 8 chicks from breeders at 48 and 60 weeks of age were placed in each pen, keeping chicks from the same treatment group together for 21 d. Chicks were fed ad libitum with a commercial broiler starter crumble for 21 d and water was provided ad libitum throughout the duration of each trial. Feed intakes (FI), body weight gain (BWG) and feed conversion ratio (FCR) were measured weekly. Data were subjected to analysis of variance using a generalized linear model of GenStat 12th edition. Simple linear regression model of GenStat 12th edition was used where appropriate. Significant improvements in offspring feed intake and body weight gain from 7-21 d were observed in chicks hatched from young breeder flocks (38 weeks) with low dietary lysine intakes (800, 930 and 950 mg/bird/d). The effect of maternal dietary lysine intake on offspring performance disappeared with the aging of the breeder flock (60 weeks). It was concluded that lower maternal dietary lysine intakes (800, 930 and 950 mg/bird/d) may improve feed intake and body weight gain from 7-21 d of broiler chicks hatched from younger breeder flocks (38 weeks).
Factors influencing breast meat yield in broilers.
(2012) Mlaba, Phindile Pearl.; Ciacciariello, Mariana.
The increased demand for breast meat of broiler chickens has challenged researchers to investigate management techniques that could be used to increase the production of this valuable commodity. Two experiments were conducted in this study; the first investigated the effect of early feeding of newly hatched broilers on breast meat yield (BMY) at market weight, and the second focused on improving BMY of broilers exposed to short daylengths by feeding higher than conventional levels of dietary protein. In the first experiment, of the 528 eggs set in the incubator, half were placed, at day 18, in hatching trays containing a commercial broiler starter feed whilst the others (the held group) were hatched conventionally. Six chicks from both fed and held groups were sampled at nine-hour intervals from the time that the first chicks hatched for a subsequent period of 36 h. After measuring their body weight these chicks were euthanised and dissected in order to measure their breast and yolk weights. Body protein, lipid and water contents were measured on each chick. At day 21, six birds from the fed and held groups were sampled, and body weight, breast weight and body protein content were measured. The yolk sac weight for fed birds was significantly reduced compared to that of held birds (P < 0.001). Both fed and held birds had the same breast weight at hatch, but at day 21 the mean breast weight of the fed birds was significantly heavier than of held birds (P < 0.05). The birds that were removed first from the hatcher had a reduced breast muscle weight compared to those that were removed last. In the second experiment, a total of 3200 day-old broiler chicks were reared in eight light-tight rooms. Four lighting regimens (12L: 12D, 16L: 8D, 20L: 4D and 24L: 0D) were randomised between rooms, with each light treatment being replicated twice. Each room was divided into four pens and 100 chicks in each pen received one of four dietary protein treatments. At day 35, three birds from each pen were sacrificed so that measurements could be made of breast, thigh, drum and wing weight, and carcass chemical composition. Breast weight increased as daylengths increased except in birds that were fed low protein diet (143 g protein/kg feed). High levels of dietary protein increased breast weight in birds on all other daylengths except for those on 12 h which showed a reduced breast muscle weight when dietary protein content was increased. The results of the first trial suggests that breast meat yield could be improved if newly hatched chicks are offered feed immediately after hatch, however the hypothesis that this increment was due to an overall increase in body protein content in the first few days after hatching could not be corroborated. The results further showed that held birds do not withdraw nutrients from breast muscle to maintain growth at hatch, this is because birds that stayed longer in the hatchery without feed showed increased breast muscle weight compared to those that were removed first. The second trial could not identify a suitable feeding programme to overcome the problem of a lower breast muscle weight that results from the use of 12 h of lighting compared to that when long daylengths are used. Highest breast weight was obtained when birds were fed high protein diet at 20 h. More research is required to further investigate the combined effect of early feeding and daylength on breast meat yield in broiler chickens.
Nature and level of trace mineral premix supplementation on growth parameters and mineral excretion in commercial broiler rations.
(2018) Franklin, Steven Bryan.; Ciacciariello, Mariana.
Commercial broiler premixes provide trace minerals (TM) such as Zinc (Zn), Manganese (Mn) and Copper (Cu) in excess of the birds’ requirements to maximize broiler performance (Untea et al., 2011). High inclusion levels of TM along with their low absorption in the GIT of the broiler, has led to increased levels of TM in their litter (Nicholson & Chambers, 2008; Manangi et al., 2012). Concerns have been raised about the accumulation of TM in the environment due to the high TM content of poultry litter. Two 35-day broiler trials were conducted at a broiler facility with 2880 day-old, Cobb 500 broiler males. Trial 1 evaluated whether decreasing inorganic trace minerals (ITM) levels (specifically Zn, Mn and Cu) in broiler diets would have a negative effect on broiler growth parameters such as body weight (BW), average daily gain (ADG), cumulative feed intake (Cum. FI) and feed conversion ratio (FCR). Zn, Mn and Cu were supplemented at 100%, 50%, 25% and 0% of the Cobb standards. Trial 2 tested whether broilers differed in their growth performance when supplemented with ITM, Organic (OTM) and Hydroxy (HTM) sources of TM (Zn, Mn and Cu) and which source would produce the least amount of TM in their excreta. No significant difference in Cum. FI and FCR was observed between the treatments in both trials for the first 21 days. On completion of Trial 1, no difference was observed in body weight between the PC, NC and 50% Cobb levels at day 35. In Trial 2 birds supplemented with HTM were 55g heavier (P<0.05) than those fed ITM at the same inclusion level at 35 days of age while those birds fed the PC, OTM and HTM showed no significant difference in their body weights. Providing broilers with HTM significantly reduced (P<0.05) Zn and Cu excretion at 35 days of age when compared to those diets containing ITM. From the study it was concluded that reducing TM levels or supplementing different sources of TM to broiler diets at lower levels showed no negative effect on broiler performance. The use of HTM significantly reduced TM mineral excretion of broilers. The results suggest that the use of HTM can maintain broiler performance while sustaining the environment.
Optimal energy to total Lys ratios for broiler performance from day old to 35 days of age.
(2017) Crots, Franscois.; Ciacciariello, Mariana.
Abstract available in PDF file.
The productive response of broiler breeder hens to lighting and growth manipulation during rearing.
(2003) Ciacciariello, Mariana.; Gous, Robert Mervyn.
This study was designed to provide information that would enable the development of a theory to predict age at sexual maturation and settable egg production in broiler breeder hens submitted to a variety of constant or increasing photoperiods and with diverse growth curves. Six trials were conducted using three strains of broiler breeder females housed in floor pens or individual cages. The treatments covered a wide range of growth profiles during the rearing period, from slow growth to achieve 2100g at 24 weeks, to fast growth achieving 2100g at 15 weeks of age. The lighting treatments included 8, 11 and 16-h constant photoperiods, photostimulation at various ages between 10 and 24 weeks, abrupt or gradual increases in daylength, and transfers to a 10, 11, 12 or 16-h final photoperiod in lay. The results show that broiler breeders exhibit photorefractoriness, and that the adult form starts developing from about 56 weeks of age. They also suggest that photorefractoriness contributes towards the accelerated decline in egg production observed at the end of the laying period. Relaxations of feed restriction during the rearing period and earlier transfers to a stimulatory photoperiod were successfully used to advance sexual maturity by up to 3 weeks compared with conventionally managed controls. Furthermore, birds subjected to constant photoperiods reached sexual maturity later than birds that had been photostimulated at 20 weeks of age. Settable egg production progressively improved when birds were transferred to stimulatory daylengths at older ages, until about 20 weeks, but subsequent delays in photostimulation did not result in any further increase in egg numbers. Delaying photostimulation of conventionally grown birds beyond 28 weeks and maintaining them on constant 8 or 16-h photoperiods negatively affected egg production. Maintaining birds on constant 11-h photoperiods had a less deleterious effect on egg production. Increasing the photoperiod from 8 to 12 h resulted in a significant improvement in settable egg production compared with birds transferred to 16 h. Prediction equations were produced to estimate mean age at sexual maturity for control birds subjected to constant photoperiods, and for birds reared on a control or fast growth curve and photostimulated at between 10 and 24 weeks of age. Data presented in this thesis suggest that, to minimise the accentuated decline in egg production typically seen late in the laying period, birds kept in light-tight houses should be transferred to photoperiods shorter than the currently recommended 16 h. Finally, photorefractoriness provides an improved understanding of the causes of erratic performance frequently observed in out-of-season flocks kept in open sided houses.
The response of broiler breeder hens to dietary lysine : hatchability, embryo growth and subsequent offspring performance.
(2011) Ruck, Shaun Bernard.; Tyler, Nicola Claire.; Ciacciariello, Mariana.
This study was conducted to determine the effects of breeder hen dietary lysine on offspring performance. In trial 1, Cobb 500 broiler breeder hens were fed 1200, 1070, 930 and 800 mg lysine/bird/d from 26 to 60 weeks of age or provided a gradual decrease from 1200 to 800 mg lysine/bird/d or a gradual increase from 800 to 1200 mg lysine/bird/d. Feed allocation was constant for all treatments at 160 g/bird/d. From each of these treatments 84 eggs were collected at 38,48 and 60 weeks of age and incubated. The different lysine treatments did not have a significant effect on the percentage hatch of the eggs at any of the recorded ages. However, hatchability, unexpectedly, decreased linearly with increasing dietary lysine, although the R2 for this was low. In trial 2, the effect of the maternal dietary lysine intake on the egg weight, yolk and albumen weights, embryo heat production and embryo growth rates of three genotypes (broiler, broiler x layer, and layer) and growth rates were assessed. The hens were fed either 920 mg lysine/bird/d (medium) or 816 mg lysine/bird/d (low). From each group 60 eggs were collected, weighed and then incubated. During the incubation from d 2 to d 18, 3 eggs were removed from each group every 2 d for eggshell temperature measurement and embryo weight measurement. There was a significant effect of lysine level on the embryo heat production of the broiler genotype with the birds from the high lysine treatment producing more heat and attaining a higher d 18 embryo weight. In trial 3, once the chicks had hatched, chick weight was recorded at 1, 7, 14, 21, 28 and 35 d. The chicks received a commercial starter and grower feed ad libitum. The broiler progeny from the birds on the high lysine treatment remained significantly heavier until d 14. The results indicate that an increased maternal lysine level improves the performance of a faster growing genotype up to 14 d of age.
The effect of varying dietary nutrient densities on performance: experimental investigations on the response of broiler chickens to different energy and lysine levels.
(2024) Ndlebe, Loyiso.; Ciacciariello, Mariana.; Tyler, Nicola Claire.
The overall objective of the study was to determine the influence of varying dietary apparent metabolizable energy (AMEn) and digestible lysine (dLys) inclusion levels on the overall growth performance of Cobb 500 broilers. Two experiments were conducted, and in each experiment a total of 1440 unsexed day-old Cobb 500 broiler chicks were randomly allocated to one of 48 pens (i.e. 30 chicks per pen) in a completely randomized block design. In experiment 1, the effect of incremental changes in dietary AMEn while maintaining a constant dLys: AMEn ratio was assessed. Experimental diets were formulated to contain eight different dietary AMEn concentrations ranging from 11.30 to 13.05 MJ/kg (+0.25MJ/kg) respectively, while adjusting dLys levels tomaintain a constant dLys: AMEnratio of 0.97. The broilers received a common broiler started diet for a period of 14 days, after which the experimental diets were introduced (Day 14-35 of the trial). Feed intake decreased linearly with incremental changes in dietary AMEn. Dietary AMEn intake and energy efficiency ratio (EER) differed significantly between treatments. Dietary AMEn increased linearly with incremental changes in AMEn, while EER exhibited a quadratic response. No significant differences in body weight gain (BWG) were observed for the entire treatment period (Day 14-35). According to the response curve equation (𝑌 = −58.952𝑥2 + 1473.9 − 6937.9), BWG was optimised at 12.55 MJ/kg. Increasing AMEn while maintaining the dLys: AMEn ratio improved feed conversion ratio (FCR), and significant differences occurred between the lowest and the highest nutrient densities. In experiment 2, the influence of varying dietary dLys levels in isoenergetic diets was evaluated. Experimental diets were formulated to contain eight different dietary dLys levels ranging from 0.95 to 1.30% (+0.05%). Dietary AMEn concentration was kept constant at 12.1 MJ/kg giving dLys: AMEn ratios 0.78, 0.83, 0.87, 0.91, 0.95, 0.99, 1.03 and 1.07. The broilers were fed a common broiler started diet for the first 14days, whereafter the experimental diets were fed from Day 14-35 of Experiment 2. Feed intake and AMEn intake were not affected by the incremental changes in dietary dLys. Energy efficiency ratio, dLys intake and digestible lysine ratio (dLysER) differed significantly between dietary treatments. Digestible Lys intake increased, while dLysER decreased with an increase in dLys inclusion level. Overall, BWG differed significantly between treatment groups, with an increasing quadratic response (𝑌 = −1119𝑥2 + 2871.7𝑥 + 301.11, 𝑃 < 0.05). Feed conversion ratio decreased (improved) linearly with increasing dLys levels. It can be concluded that broilers can sustain optimal growth performance in a range of dietary AMEn concentrations, provided that an ideal balance between dietary AMEn and nutrients is maintained. Furthermore, adjusting the dLys: AMEn ratio when feeding one dietary AMEn concentration for growing and finishing will optimise broiler performance. Keywords: broiler, digestible lysine, dietary energy, apparent metabolizable energy, energy concentration; digestible lysine: energy ratio; performance
The use of enzyme supplementation for wheat-barley diets in poultry as a means of improving productive performance.
(2010) Mokoma, Masefo Josephina.; Ciacciariello, Mariana.
The objective of the study was to evaluate the effect of an exogenous multi-blend enzyme ( -glucanase and xylanase) on the performance of the broiler chickens and laying hens fed diets based on wheat and barley. Experiments were conducted on a flock of broilers and two flocks of laying hens. In both cases feed and water were provided ad libitum. The enzyme effect of enzyme addition on the broiler performance involved 2080 day-old male and female chicks in 48 pens, allocated one of four dietary treatments (0, 50, 100 or 200g/ton enzyme supplementation), to 35 days of age. On day 35, ten birds from each treatment were sacrificed for the analysis of the digestive organs weight (gizzards and livers). The trial was divided into two phases: a starter (1 to 21 d) and grower (22 to 35 d). Feed consumption was measured weekly and birds were also weighed weekly. The investigation of enzyme effect in laying hen diets involved 896 birds for each specific period. Each replicate consisted of four cages (four birds per cage) with a common feeder; 16 hens/pen of 56 pens. Eggs were weighed three times a week, feed consumption weekly and birds every weeks. The addition of a multi-blend enzyme significantly improve body weight, body weight gain, food intake, and feed conversion ratio for both sexes (P<0.05) in broiler chickens. There was a significant improvement in egg production in laying hens (P<0.05). Egg weight and egg mass were not significantly improved. Wheat and barley have cell wall components (arabinoxylans and -glucans respectively) which have a negative effect on the nutritive value of these feeds and therefore performance in poultry fed diets based on these ingredients. Addition of an exogenous multi-blend enzyme( -glucanase and xylanase) could help reduce these effects and improve performance and digestibility values in poultry. The null hypothesis was there will be no difference between supplemented and un-supplemented diets based on wheat and barley in performance of poultry. The results of this study suggest that the inclusion of 50 g/ton enzyme helps improve poultry performance, especially in young birds.