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PubMed2002

The potential for the improvement of the nutritive value of soya-bean meal by different proteases in broiler chicks and broiler cockerels.

1. The potential for improving the nutritive value of commercial solvent-extracted, heat-treated soya-bean meal (SBM) by protease treatment was measured using growing broiler chicks and tube-fed broiler cockerels. 2. SBM was pre-treated (50 degrees C for 2 h) with water alone; at alkaline pH (initial pH 8.25) with and without protease P1 (isolated from a Bacillus species) or at acid pH (initial pH 4.5) with and without protease P2 (isolated from an Aspergillus species) and incorporated into diets (290 g SBM/kg diet) for broiler chicks (20 chicks/treatment). Only protease P2 treatment improved chick performance; from 7 to 28 d of age, chicks fed on treated SBM had greater feed intakes and gained more weight than chicks fed on untreated SBM. Both proteases P1 and P2 significantly reduced chick serum anti-soya antibodies while protease P2 treatment increased apparent ileal nitrogen (N) digestibility and apparent N retention across the whole digestive tract. 3. Two tube-feeding experiments established that, of the treated SBMs used in experiment 1, only protease P2 treatment improved apparent N digestibility and true metabolisable energy. Also it was shown that increasing the temperature at which treated SBM was dried to 60 degrees C, compared with freeze-drying or drying at 50 degrees C reduced apparent N digestibility and true metabolisable energy of SBM with no significant interactions between enzyme treatment and drying temperature for both apparent N digestibility and TME. 4. It is concluded that, overall, the nutritional value of SBM assayed in a growth trial and by tube feeding was improved by treatment with protease P2 and not by treatment with protease P1.

Animal Feed↗

PubMed2003

Improvement of the nutritive value of soybean meal by protease and alpha-galactosidase treatment in broiler cockerels and broiler chicks.

1. Tube-fed broiler cockerels were used in three experiments to measure the effect of different enzyme treatments on true metabolisable energy (TME) and true nitrogen digestibility (TND) of commercial solvent-extracted, heat-treated soybean meal (SBM). 2. In experiment 1, proteases P2 and P3 (from Aspergillus niger) and alpha-galactosidase (from A. oryzae) improved TME and TND while protease P1 (from Bacillus subtilis) had little effect. The effects of enzyme treatment were similar whether treatment was applied by pre-incubation of enzymes (proteases P1, P2 and P3, 1.0 g/kg; alpha-galactosidase, 0.1 g/kg) with SBM for 2 h at 50 degrees C or by simple mixing of enzymes (proteases P1, P2 and P3, 0.25 g/kg; alpha-galactosidase, 0.1 g/kg) with SBM prior to feeding. 3. In experiment 2, the effects of mixing SBM with each of protease P1 (0 or 0.25 g/kg), protease P3 (0 or 0.25 g/kg) or alpha-galactosidase (0 or 0.1 g/kg) alone or in all possible combinations were studied. Effects of protease P1 were limited, but protease P3 and alpha-galactosidase improved TME and TND. There were significant interactions between protease P3 and alpha-galactosidase for both TME and TND; the response when enzymes were applied together was less than that expected from application of the enzyme preparations individually. 4. In experiment 3, the effect of varying the concentration of protease P3 (0, 0.1, 0.25 and 1.0 g/kg SBM dry matter) and alpha-galactosidase (0, 0.025, 0.0625 and 0.25 g/kg SBM dry matter) mixed with SBM alone or in all possible combinations of protease P3 and alpha-galactosidase were assessed. Increases in TME and TND for both enzymes were non-linear with the greatest response occurring at the lowest concentration of each enzyme. There were also interactions between the two enzyme preparations. 5. Finally, either protease P3 (0, 0.1 and 1.0 g/kg SBM dry matter) or alpha-galactosidase (0, 0.025 and 0.25 g/kg SBM dry matter) were mixed with SBM alone or in all possible combinations and treated SBMs incorporated into semi-purified diets containing 450 g SBM/kg as the sole source of dietary N and offered to growing broiler chicks for 21 d. Similar patterns of increases in chick growth rate and diet digestibility to those recorded in experiment 3 were obtained when protease P3 and alpha-galactosidase where included in the diets. 6. It is concluded that responses measured by tube-feeding SBM treated with protease P3 and alpha-galactosidase were similar to responses obtained with growing broiler chicks. Further, these responses were obtained by simple addition of enzymes to diets and nutritive value of SBM was improved by both protease and alpha-galactosidase treatment.

Animal Feed↗

PubMed2005

Limited effect of intense genetic selection for broiler traits on ovarian function and follicular sensitivity in broiler breeders at the onset of lay.

Female chicks from 6 pure lines of broiler breeders were obtained from international broiler breeder companies. The lines were from three female and two male lines and a relaxed selection line derived from one of the male lines (M2) and maintained without selection for 25 years (generations). Replicate groups from each line were reared in floor pens and fed ad libitum. An additional group of the M2 male line was feed restricted and housed in similar pens. Twenty birds from each group were photostimulated after housing them in individual cages at 14 weeks of age. Ovarian follicular dynamics and follicular sensitivity were determined after the onset of lay. Female lines had a greater proportion of atretic follicles and more groups of multiple follicles than male lines. Body weights, fatness and age at puberty were similar in male and female lines. The relaxed selection line had more abdominal fat than any of the selected lines and the ovary contained a similar number of normal yellow follicles as the selected male line. Feed restriction decreased body weight, the numbers of yellow follicles, multiple yellow follicles and the proportion of atretic yellow follicles, and increased the age at onset of lay. The response of ovarian follicles of three different sizes to exogenous gonadotrophin stimulation with PMSG was similar in small yellow follicles, 5 to 6 and 2 to 3 mm white follicles in a female line, a male line and its relaxed line fed ad libitum. The results suggest that the original lines from which modern male-line broiler stocks are derived had a relatively large number of yellow follicles and a high propensity for multiple ovulation at the onset of lay. Separate selection for different traits in male and female lines has not had a dramatic effect on ovarian function or sensitivity to gonadotrophin stimulation.

Aging↗

PubMed2005

Transfer of nitrofuran residues from parent broiler breeder chickens to broiler progeny.

The use of nitrofuran antibiotics in food-producing animals is prohibited within the EU. Countries in the EU, as well those intending to export food to the EU, must ensure that their products are free from nitrofuran residues. As a result of recent global problems where chicken meat from a wide range of countries has been contaminated with nitrofuran metabolites, an investigation was performed to discover whether or not residues of the nitrofurans might be transferred from parent breeder chickens to their offspring broilers. Four groups of broiler breeders were each treated with one of the nitrofurans: furazolidone, nitrofurazone, nitrofurantoin or furaltadone. Residues of their side-chain metabolites, AOZ, SEM, AHD and AMOZ, were detected in the fertilised eggs at concentrations up to 1567 microg/kg. However, in the chicks that subsequently hatched from these eggs, residue concentrations of SEM, for example, were only found up to 26.6 and 32.5 microg/kg in liver and muscle, respectively, for 1-d-old chicks. Residue concentrations in tissues had fallen below the detection limit of the analytical method for 40-d-old broiler chicks, for all compounds except for semicarbazide (SEM, the nitrofurazone metabolite). Relatively high concentrations of nitrofurans are available to the newly hatched chick through the egg yolk. However, most of these residues are neither utilised nor deposited in the liver or muscle.

Aging↗

PubMed1987

[Consequences of nutritional and husbandry factors on the heat production of rats and broilers. 2. Effect of environmental temperature on the heat production of fully grown broilers and rats].

In an experiment with broilers (origin Tetra B) and with rats (albino, Wistar line) with 2 animals each, heat production was ascertained by measuring CO2 production and O2 consumption over 20 minutes after their feeding 18 h and 1 h before the beginning of measuring at ambient temperatures of 30, 25, 20, 15 and 10 degrees C. Every variant was followed through over 6 h/d in 12 measuring sections. The feed amount/ánimal and day was adapted to energy maintenance requirement. At the beginning of the experiments the broilers and rats were 14 and 21 weeks old resp. and weighed 2.2 kg and 220 g resp. The variation of the ambient temperature did not influence the heat production of the broilers. In contrast to this, the time of feeding in relation to the beginning of measuring had a distinct effect on heat production. Whereas a heat production of 342 +/- 34 kJ/kg LW0.75.d was ascertained in the postabsorptive state 18 h after the last feed intake, it increased by 11% to 393 +/- 32 kJ/kg LW0.75.d when measuring began 1 h after feeding. The very act of feed intake increased heat production by 75%. Rats showed a distinct increase of heat production caused by a decreasing ambient temperature. In the temperature range of 30-25 degrees C the increase was shallower than in the range of 25-10 degrees C. Per 1 degrees C below 25 degrees C heat production increased by 30 kJ/kg LW0.75.d. The increase was independent of the metabolism level, which was influenced by the feeding variants. The results are discussed in connection with Rubner's theory of heat compensation.

Animal Feed↗

PubMed1997

Selective enrichment of bifidobacteria in the intestinal tract of broilers by thermally produced kestoses and effect on broiler performance.

A series of kestose oligosaccharides have been produced from pyrolysis of sucrose and the effects of feeding these thermal kestoses on broiler performance and cecal microbial populations were evaluated. Eighty-four broiler chicks (day-old Hubbard x Hubbard) were fed either a nutritionally complete basal starter diet (control), the starter diet dressed with 8% of other sugars found in the thermal kestoses mixture (glucose, sucrose, and fructose), or the starter diet dressed with 10% crude thermal kestoses (2% kestoses, 8% other sugars) for a 4-wk period. Body weight and feed intake were measured weekly. After 4 wk the birds were killed, cecal contents were collected, and selected microbial populations were enumerated. Weight gains were 938, 968, and 989 g for control, other sugars, and thermal kestoses groups, respectively. There were no dietary effects on weight gain, feed conversion, or concentrations of total aerobic bacteria, coliforms, aerobically enumerated lactobacilli, total anaerobes, or clostridia. Cecal bifidobacterial concentrations were increased (P < 0.001) 24-fold in kestose-treated birds compared with controls, with bifidobacterial concentrations being 8.98, 9.09, and 10.36 log10 cfu/g cecal DM in birds fed the control, other sugars, and thermal kestoses diets, respectively. Anaerobically enumerated lactobacilli concentrations in kestose-treated birds were increased (P < 0.007) sevenfold compared with controls, with lactobacilli concentrations being 9.56, 9.53, and 10.36 log10 cfu/g cecal contents, respectively. Thermally produced kestoses altered intestinal bacterial populations in broilers and may have potential to enhance health and performance under the appropriate conditions.

Actinomycetales Infections↗

PubMed1998

Influence of broiler strain cross and dietary protein on the performance of broilers.

The purpose of this experiment was to quantify the responses of two broiler strain crosses to different dietary protein levels on performance and carcass yields. Day-old broiler chicks from a high-yield strain cross (Ross x Ross 208) and a fast-growing strain cross (Peterson x Arbor Acres) were placed in floor pens on fresh pine shavings. All birds were fed a 23% CP starter for the first 18 d. During Days 18 to 53, birds were fed either 16, 20, or 24% CP diets (3,200 kcal ME/kg). At 53 d of age, significant differences (P < 0.05) were noted in the performance of the strains. Overall, Ross x Ross birds had higher body weights (3.29 vs 3.10 kg), higher feed intakes (6.40 vs 6.11 kg), and higher carcass yields (72.51 vs 71.17%), although the differences were dependent on dietary protein levels. Strain cross had no significant effect on feed conversion (1.95 g feed: g gain vs 1.97 g:g). Results indicated that both strain cross and protein level had effects on body weight and feed intake, and there were significant strain cross by protein level interactions for body weight and carcass weight. Increasing dietary protein level increased body weights more for the Ross x Ross 208 than for the Peterson x Arbor Acres broilers. Feed conversion was indirectly proportional to dietary protein level, but was not affected by strain cross. Percentage carcass yield was greatly affected by strain (P < 0.0001), but protein level had no significant effect (P = 0.68). The significant interactions indicate that different strain crosses should have different feeding programs to maximize profitability.

Age Factors↗

PubMed2003

Growth, livability, and feed conversion of 1957 versus 2001 broilers when fed representative 1957 and 2001 broiler diets.

Body weight, feed consumption, and mortality were measured in the 1957 Athens-Canadian Randombred Control (ACRBC) strain and in the 2001 Ross 308 strain of broilers when fed representative 1957 and 2001 diets. The dietary regimens were chosen to be representative of those used in the industry in 1957 vs. 2001. The 1957 diets were fed as mash, the 2001 starter was as crumbles, and the grower and finisher diets were pellets. Feed consumption and BW were recorded at 21, 42, 56, 70, and 84 d of age to cover the two broiler strains normal span of marketing ages. Mortality was low, and the mortality of the ACRBC was approximately half that of the modem strain. Average BW for the ACRBC on the 1957 diets were 176, 539,809, 1,117, and 1,430 g vs. 743, 2,672, 3,946, 4,808, and 5,520 g for the Ross 308 on the 2001 diets at 21, 42, 56, 70, and 84 d of age, respectively. The 42-d feed conversion (FC) on the 2001 and 1957 feeds for the Ross 308 were 1.62 and 1.92 with average BW of 2,672 and 2,126 g and for the ACRBC were 2.14 and 2.34 with average BW of 578 and 539 g, respectively. The Ross 308 broiler on the 2001 feed was estimated to have reached 1,815 g BW at 32 d of age with a FC of 1.47, whereas the ACRBC on the 1957 feed would not have reached that BW until 101 d of age with a FC of 4.42.

Aging↗

PubMed2004

Components of feed efficiency in broiler breeding stock: the use of fasted body temperature as an indicator trait for feed conversion in broiler chickens.

Five trials were conducted to evaluate the usefulness of body temperature (BT) measured under conditions of mild handling stress as an indicator trait for feed conversion ratio (FCR) in broilers. The trials used males from 4 lines of broilers (a randombred control population and 3 heavy broiler lines). Birds were reared to approximately 6 wk of age and then selected for FCR testing based upon BW and conformation. At the start of the FCR test, birds were fasted for periods lasting from 18 to 48 h, and their BT were measured, which was followed immediately by initiation of an FCR test lasting 1 wk. The correlation between FCR and BT was significant in only 2 of the 5 trials. Differences between good and poor converters were generally attributed to greater gains of BW on similar amounts of feed intake. The results of the current trials indicate gain on test is the primary factor affecting FCR and that BT is not a reliable predictor of FCR.

Animal Feed↗

PubMed1988

Fat deposition in a broiler sire strain. 4. Performance of broiler progeny of four differently selected sire lines.

Cocks from four lines selected for a low amount of abdominal fat (AF), a favorable feed conversion ratio (FC), and high body weight after restricted (GR) or ad libitum (GL) feeding were mated to commercial broiler breeder hens. A total of 3,600 broiler progeny in three hatches from these matings was reared by line in litter pens. At 41 days of age GR and GL line progeny had significantly heavier body weights, poorer feed conversion ratio, and higher percentages of abdominal fat than AF and FC line progeny. At comparable body weights (AF, 1,893; FC 1,918; GR, 1,848; and GL, 1,897 g) feed conversion was most favorable for FC line progeny (1.72), AF and GL line progeny did not differ (1.77), and GR line progeny had the poorest feed conversion ratios (1.79). The AF line progeny had the lowest percentage abdominal fat (1.88%), followed by FC line progeny (2.20%), GL line progeny (2.91%), and GR line progeny (3.10%). As in the pure lines, selection for body weight after restricted feeding was not effective in obtaining leaner and more efficient chickens. When compared with differences between pure lines, results of the broiler progeny matings indicate that body weight, feed conversion, and percentage abdominal fat are inherited largely in an additive manner.

Abdomen↗

PubMed1994

Selection for high and low threshold body weight at first egg in broiler strain females. 4. Photoperiodic drive in the selection lines and in commercial layers and broiler breeders.

A two-way selection program, carried out for high and low threshold BW at onset of lay (ThrWtLay), decreased photoperiodic drive of the high line (HL) relative to the low line (LL). Photoperiodic drive in modern broiler breeder females was compared to layer females in experiments using the HL and LL lines, a commercial layer cross (LX), and a commercial broiler breeder female line cross (BX). Treatment groups were: NS, natural decreasing light to 20 wk, followed by natural light supplemented to 16 h daily with artificial light; NN, natural decreasing light to end of experiment; DD, dark room from hatch to end of experiment; ND, natural decreasing light to 20 wk, dark room thereafter. Under NS, mean age and BW at first egg was greater for the HL line than for the LL line. The difference increased by a further 8.9 d and 217.5 g under NN. Similarly, under NS, mean age and BW at first egg was greater for BX than for LX, and the difference increased by a further 22.6 d and 256.1 g under NN. These interactions indicate greater photoperiodic drive of LX and LL stocks relative to the HL and BX stocks. Prepeak and peak egg production (EP) was greatest for the LX, lower for the LL, and lower yet for HL and BX. Photoperiodic drive may be of major importance in determining prepeak and peak EP. Except for the DD treatment, age and BW of the LX cross at first egg were virtually identical across treatments, those of the LL line were similar, whereas those of the HL and BX stocks showed differences. Similarly, EP curves of the LX cross were virtually identical across treatments, those of the LL line were relatively uniform, but those of the HL and BX stocks again showed great differences. Standard deviation and coefficient of variation of peak EP were very low for the LX cross, still low, but significantly greater for the LL line, and significantly greater yet again for both HL and BX stocks. Thus, increased photoperiodic drive may also be associated with greater stability of reproductive performance. Selection for early onset of lay on release from feed restriction may provide a means of increasing photoperiodic drive and consequent reproductive performance of broiler breeders.

Age Factors↗

PubMed1994

Growth, livability, and feed conversion of 1957 vs 1991 broilers when fed "typical" 1957 and 1991 broiler diets.

The relative contributions of genetic selection and dietary regimen on the performance of broilers was assessed. Body weight, feed consumption, mortality (M), and the degree of tibial dyschondroplasia (TD) were measured in the 1957 Athens-Canadian Randombred Control (ACRBC) strain of broilers and in the 1991 Arbor Acres (AA) feather-sexable strain when fed "typical" 1957 and 1991 diets. Energy and protein levels, vitamin and mineral packs, and the coccidiostats used in the two dietary regimens were chosen to be representative of those in use by the industry for the two time periods. Eight treatment groups, i.e., two strains, two sexes, and two dietary regimens, were assigned into four blocks of eight litter floor pens for grow out. The 1957 diets were fed as mash, and the 1991 starter and grower diets were fed as crumbles and pellets, respectively. Feed consumption and BW were recorded at 21, 42, 56, 70, and 84 d of age, a period covering the normal marketing ages for the two broilers. Mortality and the cause of death was recorded daily. The incidence and severity of TD was assessed using a Lixiscope at 42 d of age. Average BW were 190, 508, 790, 1,087, and 1,400 g for the ACRBC on the 1957 diets vs 700, 2,132, 3,108, 3,812, and 4,498 g for the AA on the 1991 diets at 21, 42, 56, 70, and 84 d of age, respectively. The 1991 diets increased the BW of the AA by an average of 14% (20% at 42 d, but only 8% at 84 d) and of the ACRBC by 22%. The BW advantage for the 1991 diet over the 1957 diet for the AA was less for males than for females after 42 d of age, and the advantage decreased with age, probably due to the increasing incidence of leg problems. The M for AA was 9.1% vs 3.3% for the ACRBC at 42 d. Most of the ACRBC M occurred before 21 d, whereas M occurred throughout for the AA, with most after 21 d due to flip-overs and ascites. The feed conversion at 42 d for the ACRBC on the 1957 diet was 3.00 vs 2.04 for the AA on the 1991 diet. The AA on the 1991 diet had a 48.6% incidence of TD vs 25.6% on the 1957 diet. The ACRBC had approximately 1.2% TD on both diets. The TD was more severe with the 1991 diet.

Animal Feed↗

PubMed1994

Carcass composition and yield of 1991 vs 1957 broilers when fed "typical" 1957 and 1991 broiler diets.

Whole carcass yield and the yield of parts (i.e., wings, saddle and legs, Pectoralis major, Pectoralis minor, breast skin, rack, abdominal fat pad, heart, and lungs), as well as whole carcass analysis for fat, moisture, and ash, were measured in the 1957 Athens-Canadian Randombred Control (ACRBC) and in the 1991 Arbor Acres (AA) feather-sexable strain, when fed "typical" 1957 and 1991 diets. Using the average of both sexes, the carcass weights of the 1991 birds on the 1991 diets were 4.4, 3.9, and 3.5 times heavier than those from the 1957 ACRBC on the 1957 diet at 43, 71, and 84 d of age, respectively. Birds fed the 1991 diets had significantly heavier carcass weights than those fed the 1957 diets. Hot carcass yield of the AA broiler (mean of both sexes) was approximately 6 to 7% higher at the same age than for the ACRBC. Water uptake in the carcass (following a 60-min immersion in ice water) was approximately 2 to 2.5% higher in the ACRBC than in the AA broiler. Yield of saddle and legs as a percentage of live BW was about 4% higher in the AA than in the ACRBC. Dietary regimen did not affect the yield of saddle and legs. Males had 2 to 3% more saddle and legs than the females. The yield of total breast meat for the AA was approximately 3% higher (mean = 16.9%) than for the ACRBC over both sexes and all ages. Breast yield on the 1991 diets was approximately 1.2% higher for the AA than for the ACRBC. Females had slightly higher breast yield (1%) than males. The AA broiler had consistently heavier fat pads and higher percentage carcass fat at the same age and on the same diet than did the ACRBC. The percentage carcass fat was significantly higher on the 1991 vs the 1957 diet and in females vs males. The male-female difference in percentage carcass fat increased with age. Heart and lung size as a percentage of live BW were lower in the AA than in the ACRBC.

Animal Feed↗

PubMed1991

Effect of monensin and its metabolites in broiler litter on sheep consuming the broiler litter.

Two trials were conducted to determine the effect of monensin in broiler litter on sheep receiving the broiler litter in their diets. Broiler litter from chickens fed monensin as a coccidiostat, and from chickens receiving no coccidiostat, was included at a level of 30% in 2 sheep diets. In a further 2 treatments, monensin (15 mg kg-1) was added to each of the 2 diets to give a 2x2 factorial experimental design. In the first trial, copper (20 mg kg-1 feed) was added to the diets. These lambs were fed individually at a slightly restricted level of intake. No differences between treatments were observed in feed intake, average daily gain or efficiency of feed utilisation or in the concentrations of zinc, iron and manganese in the liver, glutathione peroxidase in erythrocytes and creatine kinase concentrations in the plasma. Hepatic copper content and copper retention in the livers of the sheep receiving the added monensin were significantly higher (P less than 0.05 and less than 0.01 respectively) than in those not receiving added monensin. The aspartate transaminase and alkaline phosphatase concentrations in the plasma of these sheep were also higher (P less than 0.05) than in those not consuming added monensin. In the second trial, the lambs were group-fed according to treatment and received the diets on an ad lib basis. The mean intakes of the groups receiving the diets with the added monensin, were lower than the intakes by the other groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Animal Feed↗

PubMed1987

Broiler pulmonary hypertension syndrome. I. Increased right ventricular mass in broilers experimentally infected with Aegyptianella pullorum.

Infection with the obligatory intra-erythrocytic anaplasma-like rickettsia Aegyptianella pullorum in 4-week-old broilers at a moderate altitude of 1,200 m produced a significant increase in the mean relative right ventricular (RV) mass (RV: TV) from 0.23 in the controls to 0.31 in the infected group. This was accompanied by an increase in the number of birds suffering from severe RV hypertrophy from 14.3% in the controls to 50% in the infected group. Pulmonary hypertension and subsequent RV hypertrophy could have been caused by the severe anaemia experienced in the course of the infection or by metabolic or biochemical action of A. pullorum. As the agent does not occur on commercial broiler farms, it cannot play a practical role in the broiler ascites syndrome.

Anaplasmataceae Infections↗

PubMed1982

[Energy maintenance requirement and energy requirement for protein retention in growing rats and broilers. 4. Energy requirement for protein retention in broilers].

The results of measurings of the total metabolism from experiments with 6 male broilers (origin: Tetra B) each, which mainly served the ascertainment of energy maintenance requirement (cf. 2) in the growth range between 100 and 2,000 g with alternating experiment phases on the maintenance and growth level, have also undergone interpretation for the further characterisation of the energy requirement for protein retention. Caused by the sequence of periods chosen, there were compensatory growth effects. Energy retention in % of gross energy varied between the experiments in the limits of 24 and 39%, and concerning energy retention per animal and day there were differences up to 100% between the experiments. The share of protein energy retention in energy retention on average amounted to 38% after a medium-high protein supply and 54% after a high protein supply. The utilisation of metabolisable energy for energy retention was significantly lower from rations of a high protein level (40% crude protein) than from those of a medium-high protein level (20% crude protein). Assuming an energy requirement for fat retention of 1.2 J metabolisable energy per J retention, a requirement of metabolisable energy for 1 J protein retention of 1.68; 1.66 and 1.86 was ascertained in the 3 experiments by means of regression analysis. An energy requirement for maintenance of 423 (30 degrees C), 511 (25 degrees C) and 432 kJ metabolisable energy/kg live weight 0 75 X d (30 degrees C) correlated with these requirement values. Energy requirement for protein retention increased significantly with N-intake and decreased significantly with the daily protein retention rate. There was no dependence on the live weight of the broilers.

Animals↗

PubMed1987

[Energy and protein concentration of broiler rations in Cuba. 2. Female broilers in winter].

Four energy concentrations (10.5, 11.5, 12.6 and 13.6 MJ ME) and four protein concentrations (15.0, 17.5, 20.0 and 22.5% CP) were tested with a total of 1,900 female broilers of the breed White Plymouth Rock in their first 56 days of life in 16 experiment groups. The animals were kept in cages and were directly exposed to the natural Cuban winter temperatures from their 15th day of life. As six repetitions were carried out in every test group, the results could be variance-analytically calculated. In winter the female broilers of the breed White Plymouth showed a lower intake of feed, metabolic energy and crude protein than male animals. They achieved a lower live weight, lower amount of body protein and fat and worse feed, protein and energy utilisation. Possibilities are shown to meet the crude protein and energy requirement in monophase feeding systems with 11.5 MJ ME and 20% CP or with 12.6 MJ ME and 17.5 or 20% CP.

Animal Feed↗

PubMed2000

Effects of relative humidity during the last five days of incubation and brooding temperature on performance of broiler chicks from young broiler breeders.

Broiler hatching eggs were subjected to one RH condition (53% RH) from 0 to 16 d and switched to one of three different RH conditions (43, 53, or 63%) from transfer at 16 d to pull time at 21.67 d of incubation. The broiler breeder ages were 27, 29, and 31 wk for Trial 1, and 26, 28, and 30 wk for Trial 2 in Experiment 1. For both trials, BW at hatch, BW at pull, hatch time, and chick weight loss between hatching and pull were measured. All unhatched eggs were opened and examined macroscopically. Experiment 2 was conducted using the chicks produced in Experiment 1. The chicks were immediately placed after pull and randomly distributed by sex into brooding pens by RH treatment in Trial 1, and by sex, RH, and brooding temperature in Trial 2. Two brooding conditions, warm and cool, were used in Trial 2. Body weight at placement, BW gain to 12 d, feed conversion, and mortality were recorded. There was no effect of RH treatment on fertile hatchability. Body weight at hatch, pull, and placement increased with hen age. Mortality was higher for the late-hatching chicks in the warm brooding conditions in Trials 1 and 2 of Experiment 2, whereas mortality was significantly greater for the early-hatching chicks and those chicks hatched at 43% RH under the cool-brooding temperature conditions. Relative humidity treatment had no effect on chick performance in the presence of warm brooding conditions. Warm brooding conditions improved BW gain to 12 d compared with cold brooding conditions. Overall, optimal chick performance was achieved at 53% RH. Chick quality problems that may be due to high or low RH during incubation can be ameliorated by proper brooding conditions.

Animals↗