The effect of low-density diets on broiler breeder development and nutrient digestibility during the rearing period

Effects of different feeding strategies on behavior and performance in broiler breeder pullets

This study examined the effects of different feeding strategies (diluted diets and feeding frequency) on the behavior and performance of broiler breeder pullets. A total of 3,200 1-day-old female pullets (Ross 308) were randomly distributed over 16 floor pens in 4 rooms and allocated to 1 of 4 treatments: (1) control diet once a day (CON), (2) 20% diluted diet once a day (20-ON), (3) 20% diluted diet twice a day (20-TW), and (4) 30% diluted diet twice a day (30-TW). All the pullets of the different treatments were fed to the same body weight (BW) profile. The 30-TW pullets had the highest and the CON pullets the lowest feed intake, with the 20-ON and 20-TW pullets showing intermediate values. Total water intake was the highest for the 30-TW pullets, followed by the 20-TW and 20-ON pullets, and was the lowest for the CON pullets (P < 0.001). The pullets fed twice a day had the highest total water-to-feed ratio, and the pullets fed once a day had the lowest ratio (P = 0.003). Feeding pullets twice a day yielded the highest average BW uniformity, while the pullets fed once a day had the lowest BW uniformity (P = 0.003). Total mortality was lower in the 20-TW and 30-TW pullets than in the 20-ON pullets, which was primarily caused by fewer dead and graded pullets. The pullets fed twice a day showed overall more eating, more drinking and less sitting, object pecking, and aggressive pecking. The behavior pattern during the daylight period was different for the pullets fed twice a day. Pullets on the diluted feeding strategies were less eager to approach the novel feeder and ate less feed (P = 0.002). In conclusion, feeding pullets with adjusted feeding strategies (feeding twice a day and up to 30% diluted diets) resulted in improved behavior and welfare expressed in decreased stereotypic pecking behavior, and lower eagerness to approach the novel feeder with lower feed intake, with improved BW uniformity and decreased mortality.

Significance of successive feeding of sources of n-3 fatty acids to broiler breeders and their progeny on growth performance, intestinal lesion scores, lymphoid organs weight and plasma immunoglobulin A in broiler chickens challenged with Eimeria

The study examined the effects of successive feeding of sources of n-3 PUFA to broiler breeders (BB) and their progeny in broiler chickens challenged with Eimeria. The BB were fed: 1) control (CON), corn-soybean meal diet, 2) CON + 1 % microalgae (DMA), as a source of DHA and 3) CON + 2.50% co-extruded full fat flaxseed (FFF), as a source of ALA. Eggs were hatched at 34, 44, and 54 wk of age. Posthatch treatments (BB-progeny) were: CON-CON, DMA-CON, FFF-CON, DMA-DMA and FFF-FFF with diets formulated for starter (d 1-10) and grower/finisher (d 11-42) phases. All chicks were orally challenged with Eimeria (E. acervulina and E. maxima) on d 10. Relative to CON, DMA and FFF increased concentration of n-3 PUFA by ≥ 2-fold in hatching eggs and progeny diets. There were no (P > 0.05) interactions between treatment and BB age on d 0 to 10 growth. In general, BB age affected (P < 0.05) growth performance throughout the study. In the starter phase, successive exposure to DHA and ALA improved FCR over CON-CON (P < 0.01). The interaction between treatment and BB age in grower/finisher was such that DHA exposure to younger BB resulted in poor growth performance (P < 0.05) relative to exposure to older BB. In contrast, exposure to ALA had similar (P > 0.05) growth performance irrespective of BB age. Moreover, successive exposure to ALA resulted in higher BWG, breast weight and lower FCR compared to successive exposure to DHA (P < 0.05). There were no (P > 0.05) interactions between treatment and BB age on the intestinal lesion scores, lymphoid organ weights and concentration of plasma immunoglobulin A (IgA). Successive exposure to DHA resulted in higher (P = 0.006) jejunal lesion scores than CON-CON birds. The results showed that successive exposure of DHA and ALA improved FCR relative to non-exposed birds in the starter phase. However, responses in the grower/finisher phase depended on n-3 PUFA type, with birds on successive ALA exposure supporting better growth and breast yield than birds on successive DHA exposure.

Effect of feed form and nutrient density on growth performance, blood parameters, and intestinal traits in broiler breeder pullets

This study was conducted to evaluate the effect of feed form and nutrient density on growth performance, blood parameters, and intestinal traits of broiler breeder pullets during grower (7-19 wk) and pre-breeder (19 weeks to 5% production) periods. A total of 450 female broiler breeder pullets were used in a completely randomized design with a 3 × 2 factorial arrangement including 3 feed forms (mash, crumble, and pellet) and 2 nutrient densities (standard diet with the nutrient requirement of Ross 308 parent stock nutrition specification, and diluted diet by using sunflower hull to have 10% lower nutrient than the standard diet). Five replicates with 15 pullets per replicate were allocated to each of the 6 treatments. Blood samples were collected at 19 wk of age. Egg production reached 5% in the mid of 25 wk. Results showed that pullets fed crumble or pellet diets had greater body weight gain and a lower feed to gain ratio (F:G; P < 0.001). Diet dilution led to a decrease in body weight gain while increasing the F:G (P < 0.05). Pullets fed the pellet diets had shorter eating times than those fed crumble diets, whereas the longest eating time belonged to pullets fed mash diets (P < 0.001). Pullets fed pellet diet had a greater heterophil to lymphocyte (H/L) ratio than those fed crumble or mash diets (P = 0.007). Diluting the diet led to a decrease in the H/L ratio (P = 0.026). Neither feed form nor nutrient density had a significant effect on body weight uniformity, blood glucose and lipid concentrations, liver enzyme activities, and intestinal traits (P > 0.05). It can be concluded that pelleted or crumbled diets with lower nutrient density can be considered in broiler breeder's pullets feeding with no detrimental effect on their performance or health state.

Effects of diet density and feeding frequency during the rearing period on broiler breeder performance

1. An experiment was conducted to study the effects of diet density and feeding frequency during the rearing period on broiler breeder performance between three and 40 weeks of age.2. A total of 960 female one-day-old chicks (Ross 308) were randomly allocated to 24 floor pens (12 pens in two rooms). On day 21 pullets were assigned to a 2 × 2 factorial arrangement including two diets (control (CON) or 16% diluted (DIL)) and two feeding strategies (fed once (FO) or twice (FT) a day). The FO pullets were fed at 0815 h (100%) and FT pullets at 0815 h (60%) and 1215 h (40%). Water was provided by nipple drinkers with drip cups during 7 and 8 h in the rearing and laying period, respectively.3. Body weight (BW) and water intake were measured weekly and BW uniformity at 10 and 20 weeks of age. Litter characteristics were measured at 10, 15, and 20 weeks of age. During the laying period, egg production and incubation characteristics were recorded.4. The DIL pullets received a higher feed allowance in combination with similar water intake which resulted in a lower water/feed ratio compared to the CON pullets resulting in a higher DM content of the litter and improved litter quality. The higher feed allowance resulted in a 20% higher total manure production at 20 weeks of age. The FT pullets showed a lower body weight (BW) CV at 10 weeks of age; however, no effect was found at 20 weeks of age. During the laying period, FT pullets tended to have earlier onset of lay, higher total egg production at 30 weeks of age and better fertility.5. It was concluded that alternative feeding strategies can positively influence production performance during both the rearing and laying period.

Physiological parameter values for physiologically based pharmacokinetic models in food-producing animals. Part II: Chicken and turkey

Physiologically based pharmacokinetic (PBPK) models are growing in popularity due to human food safety concerns and for estimating drug residue distribution and estimating withdrawal intervals for veterinary products originating from livestock species. This paper focuses on the physiological and anatomical data, including cardiac output, organ weight, and blood flow values, needed for PBPK modeling applications for avian species commonly consumed in the poultry market. Experimental and field studies from 1940 to 2019 for broiler chickens (1-70 days old, 40 g - 3.2 kg), laying hens (4-15 months old, 1.1-2.0 kg), and turkeys (1 day-14 months old, 60 g -12.7 kg) were searched systematically using PubMed, Google Scholar, ProQuest, and ScienceDirect for data collection in 2019 and 2020. Relevant data were extracted from the literature with mean and standard deviation (SD) being calculated and compiled in tables of relative organ weights (% of body weight) and relative blood flows (% of cardiac output). Trends of organ or tissue weight growth during different life stages were calculated when sufficient data were available. These compiled data sets facilitate future PBPK model development and applications, especially in estimating chemical residue concentrations in edible tissues to calculate food safety withdrawal intervals for poultry.

The effect of alternative feeding strategies on the feeding motivation of broiler breeder pullets

Due to genetic selection for fast growth and high breast meat yield, commercial strains of broiler chickens and broiler breeders are predisposed to high feed intake; however, feeding broiler breeders ad libitum impairs their health and reproductive performance. Broiler breeders are feed-restricted throughout rearing to maintain health and performance, yet feed restriction results in hunger, feeding frustration and lack of satiety. The objective of this study was to examine the effect of alternative feeding strategies, including feed additives (separately or combined) and a fixed non-daily feeding schedule, on the feeding motivation and welfare of broiler breeders during rearing. At 3 weeks of age, 180 Ross 308 breeder pullets were allocated to 90 cages and fed with one of five isocaloric treatments: (1) daily control diet (control), (2) daily calcium propionate diet (CaP), (3) daily soybean hull diet (SBH), (4) daily alternative diet (alternative: CaP + SBH) and (5) 4/3 control diet (four on-feed days and three non-consecutive off-feed days per week). The CaP diet included calcium propionate at 1.4% from 3 to 6 weeks of age, and at 3.2% from 7 to 12 weeks of age, and the SBH diet contained soybean hulls included at 40%. The alternative diet included both soybean hulls and calcium propionate at the same inclusion rate as the SBH and CaP diets, respectively. Pullets were weighed and scored for feather coverage every week. A feed intake test was conducted at 3, 4, 8, 10 and 11 weeks of age for 10 min during on- and off-feed days. At 12 weeks of age, feather samples were analysed for fault bars. Data were analysed using linear mixed regression models, with cage nested in the models and age as a repeated measure. At 4 weeks of age, pullets fed soybean hull-enriched diets (SBH and alternative diets) and those on the 4/3 schedule had lower feed intake than control pullets (P = 0.02). Feathers from pullets fed the SBH diet had fewer fault bars than those fed the CaP diet (P = 0.04). The results indicated that the inclusion of soybean hulls (alone or combined with calcium propionate) and a 4/3 feeding schedule can reduce feeding motivation of broiler breeders during early rearing.

Effect of fibrous diet and vitamin C inclusion on uniformity, carcass traits, skeletal strength, and behavior of broiler breeder pullets

This experiment studied the effect of broiler breeder nutritional strategies on uniformity, carcass traits, tibia parameters, and behavior during rearing and prebreeder periods (up to 22 wk of age). One-day-old pullets (n = 384) were randomly assigned to 4 treatments arranged as a 2 × 2 factorial, with 2 fiber levels (control vs. fibrous diet, 15% diluted in AMEn and nutrient content) and 2 vitamin C feed inclusions (0 vs. 200 mg/kg). At 6, 15, and 22 wk, blood sampling was carried out (4 birds/replicate) to determine serum alkaline phosphatase (ALP) levels, and behavior was observed by visual scan sampling. At 22 wk, carcass traits, tibia parameters, and intestinal morphology were assessed (2 birds/replicate), and tail- and wing-feather integrity of all birds were scored. Fibrous diet did not modify BW uniformity, mortality, or tibia growth when compared with control diet. Pullets fed the fibrous diet had lower tibia breaking strength, elastic modulus, and ash content values (P < 0.05). They also had lower ALP serum level at 6 and 22 wk (P < 0.05), their breast muscle was less developed (18.5 vs. 19.8%, P < 0.05), and their abdominal fat deposition was higher (1.14 vs. 0.87%, P < 0.05). At 15 and 22 wk, they performed, on average, 97% less grasping feather pecking and 45% less non–food object pecking behaviors, and their wing-feather score was lower (P < 0.05) at 22 wk. Tail- and wing-feather scores of the control treatments were reduced by vitamin C inclusion (tail: 0.30 vs. 1.15, P < 0.05; wing: 0.98 vs. 1.26, P < 0.05) at 22 wk. In conclusion, fibrous diet improves carcass traits (reduces breast muscle and increases abdominal fat deposition), deteriorates bone mineral deposition and thus skeletal strength, and reduces stereotypic behaviors, improving wing-feather integrity. Vitamin C inclusion improves tail- and wing-feather integrity of lower in feed allowance.

Growth curve and diet density affect eating motivation, behavior, and body composition of broiler breeders during rearing

The aim of this work has been to assess the effect of diet density [control (CON) or 15% diluted (DIL)] and growth curve [recommended by the genetic line (RBW) or 15% heavier (HBW)] and their interaction on BW uniformity, feeding motivation, behavior, and body composition of broiler breeder pullets. A total of 3,000 one-day-old female breeders Ross 308, distributed in 20 pens, was randomly assigned to each treatment. Feed allowance was weekly adjusted to reach the desired BW. Feed was provided as pelleted (zero to 3 wk) and crumble (4 to 19 wk). Time eating was measured at 7, 11, and 19 weeks. A feeding rate test was performed after 11 weeks. Behavior was observed at 9 and 15 wk, by visual scan. At 6, 13, and 19 wk of age, one bird/pen was slaughtered for weighing different organs and analyzing the composition of empty whole bodies. Treatments did not affect BW uniformity; relative weights of the ovary, oviduct, or gizzard; or protein content of empty BW. Time eating varied with the growth curve at 19 wk (P < 0.05), HBW pullets spent 19 more min eating than RBW pullets. DIL led to 4 and 8 more min eating at 19 wk for pullets of RBW and HBW (P < 0.05), respectively. Pullets fed DIL consumed 30% (P < 0.05) less during the feeding rate test when kept on a restricted regimen, and they had lower compensatory energy intake after ad libitum feeding than those fed CON, indicating lower feeding motivation. Behavior was affected by the age and by the time of the d measured, but it did not change with the treatments. Birds spent most time pecking objects (50%), feeding (28%), and drinking (17%). Pullets fed DIL had 8% lower breast yield at different ages and higher empty digestive tracts at 6 weeks. Body composition varied with age; fat content increased from 12.7 to 15.9 to 19.8% for 6, 13, and 19 wk, respectively. The lowest body fat was observed for RBW pullets fed DIL (P = 0.003) at 19 weeks. Feeding DIL diets to HBW pullets could be done to increase the time spent eating and reduce their feeling of hunger without negative effects on body composition. However, its influence on behavior and BW uniformity was not proved.

Utilization of soy hulls, oat hulls, and flax meal fiber in adult broiler breeder hens

A total of 72, 65-week-old broiler breeder hens (Ross 308, BW 4,190 ± 45 g) was placed in individual cages to investigate utilization of fiber in soy hulls (SH), oat hulls (OH), and flax meal (FM). Birds were adapted to cages for 10 d prior to allocation (n = 18) to broiler breeder ration (control) or control mixed with either of the 3 fiber sources (wt/wt) added to supply equal amounts of neutral detergent fiber (NDF) ∼21% and TiO2. The daily feed allocation was based on 4% BW. Feed intake (FI) was monitored daily, and grab excreta samples were taken on d 16 and 17. On d 18, all birds were weighed and killed 2 h post feeding to measure ceca digesta pH and short chain fatty acids (SCFA). Relative to the control birds, birds receiving fiber lost (P < 0.05) BW due to decreased (P < 0.05) FI. The BW changes were respectively +80, -174, -133, and -585 g/bird for control, SH, OH, and FM, and corresponding FI was 1,062, 918, 885, and 590 g/bird. Birds fed FM retained higher (P < 0.05) NDF than birds fed either SH or OH. The ceca digesta pH was lower (P < 0.05) in birds receiving added fiber relative to control. However, ceca digesta pH of FM fed birds was lower (P < 0.05) than in birds fed either SH or OH, which were in turn similar (P > 0.05). Birds fed FM had higher (P < 0.05) concentration of butyric acid than birds fed the control diets, while birds fed SH and OH had intermediate butyric acid concentration. Acetic acid and total SCFA concentrations were higher (P < 0.05) in birds fed OH diet than in birds fed control but was similar (P > 0.05) to that in birds fed either SH or FM. In conclusion, short term feeding of fibrous feed ingredients reduced BW linked to reduced FI. Fiber sources exhibited differences in utilization reflective of chemical characteristics.

Comparative effects of corn-based diet and phase-fed cassava-based diet on growth rate, carcass characteristics and lipid profile of meat-type ducks

Objective

This experiment was conducted to evaluate the effects of a corn- or cassava- based diet on the production of meat-type ducks.

Methods

Four hundred day-old ducks were used in this experiment. They were divided into five groups with each group replicated eight times. The ducks fed the corn-based diets served as the control group. The four other groups comprised different treatments, with each one given the cassava-based diet based on phase-feeding. Three treatments were fed the cassava-based diet from 16, 28, and 35 d; respectively up to 42 d of age and the other group was fed the cassava-based diet from 1 to 42 d of age.

Results

The results indicated that ducks on either the corn- or cassava-based diets were similar in growth during 1 to 9 d of age. However, toward 35 to 42 d, the cassava-diet produced a higher weight gain (p<0.05). The cassava-based diet was better than the corn-based diet at increasing the outer and inner breast weights at 28, 35, or 42 d (p<0.05). In contrast, the corn-based diet was better at increasing abdominal fat (p<0.05). The two diets did not differ in their effects on the serum triglyceride, cholesterol, high-density lipoprotein-cholesterol, low-density lipoprotein-cholesterol, very-low-density lipoprotein-cholesterol, and liver cholesterol. The corn-based diet, however, caused a highly significantly greater level of liver triglyceride (p<0.01).

Conclusion

The results of this study suggest that both the cassava- and corn- based diets are similar in their effect on meat-type ducks during the starter stage but toward the finisher stage, the cassava-based diet has a better influence on weight gain and carcass characteristics.

Effect of feeding different dietary levels of energy and protein on growth performance and immune status of Vanaraja chicken in the tropic

AIM

The present study was conducted to observe the effect of feeding dietary level of energy and protein on growth performance and immune status of Vanaraja chicken in the tropic.

MATERIALS AND METHODS

The experiment was conducted for 56 days on 540 1-day-old chicks, which were individually weighed and distributed into nine groups having 60 birds in each. Each group was further subdivided into triplicates having 20 birds in each. Nine different experimental rations were formulated with three levels of protein, viz., 17%, 19%, and 21%; each with three levels of energy (2600, 2800, and 3000 kcal metabolizable energy [ME]/kg), respectively. Group T8 serves as control fed with 21% protein and 2800 kcal energy as per Project Directorate of Poultry, Hyderabad given requirement. Feed consumption, live weight gain, body weight change, and feed conversion ratio (FCR) were calculated based on the amount of feed consumed every week. All the birds were vaccinated following standard protocol. The hemagglutination inhibition (HI) test have been performed to assess the immunity potential of birds due to dietary effect, and serum samples were subjected to HI test at 7, 14, 21, and 28 days of age. Finally, economics of broiler production was calculated on the cost of feed per kg live weight gain.

RESULTS

This study revealed that the effect of feeding different levels of energy and protein on growth parameters such as body weight gain and FCR was found to be significantly higher (p<0.05) containing 19% and 21% crude protein with 3000 kcal ME/kg in Vanaraja birds. There was a gradual increase in antibody titer against New castle disease virus as the level of protein and energy increase. It is speculated that the better body weight gain corroborate health and antibody titer. Moreover, the better immune response recorded in the study might be due to better nutrient utilization and its extension toward the better immune response. Higher energy with medium protein diet positively reflects to obtain desirable performance economically.

CONCLUSION

It was positive inclination toward ration containing high protein and energy which influence the immune response of Vanaraja birds to obtained desirable performance economically also.

Influence of different concentrations of metabolisable energy at constant ratio to dietary protein, lysine, methionine, calcium and phosphorus on the performance of White Leghorn layers in the tropics

An experiment was conducted to study the effect of nutrient density on the performance (21–72 weeks of age) of White Leghorn layers reared in an open-sided poultry house in the tropics. Six diets with graded levels (9.62–11.72 MJ/kg) of metabolisable energy (ME) with an increment of 0.42 MJ were formulated. Concentrations of crude protein, lysine, methionine, calcium and non-phytate phosphorus were kept constant to ME in all diets (15.9, 0.73, 0.35, 3.19 and 0.31 g/MJ ME, respectively). At 21 weeks of age, a total of 5280 birds was distributed randomly in 4-bird colony cages and 22 such cages in a row constituted one replicate. Each diet was fed ad libitum to 10 replicates from 21 to 72 weeks of age and performance parameters were recorded at 28-day intervals (period, 1–13). Egg production (EP) increased (P < 0.05) with increasing dietary ME and maximum response in EP was observed when dietary ME levels ranged between 10.93 and 11.69 MJ/kg during the majority of periods, while in periods 6, 7 and 8 (summer, 28−37°C), maximum EP was observed at higher ME levels in diet (11.64–11.69 MJ/kg diet). Feed intake (P < 0.01) decreased, feed efficiency (P < 0.01), egg mass (P < 0.01) and weight gain (P < 0.05) improved quadratically with increase in dietary ME concentration. Maximum feed efficiency was observed at 11.36 MJ ME/kg diet during 21–72 weeks of age. Egg shell defects were not influenced (P > 0.05) by dietary nutrient density. Mortality reduced quadratically with increase in dietary ME concentration and mortality was minimum at 11.64 MJ ME/kg diet. Based on results from the experiment it was concluded that White Leghorn layers (21–72 weeks of age) require 11.36 MJ ME/kg diet for maximum egg production, feed efficiency and egg mass with better liveability. The calculated intake of metabolisable energy, crude protein, lysine, methionine, calcium and non-phytate phosphorus in layers fed 11.30 MJ ME/kg diet was 1.157 MJ, 18.42 g, 865 mg, 409 mg, 3.68 g and 358 mg per bird per day, respectively.