Effect of dietary protein,essential and non‐essential amino acids on the performance and carcase composition of male broiler chickens

1. The present study was conducted to determine the possibility of using low‐protein broiler diets supplemented with synthetic amino acids. The effects on performance, carcase composition and nitrogen retention were evaluated.)

2. A starter diet was given, ad libitum, from 7 to 21 and a finisher diet from 21 to 42 d of age. Body weight, weight gain, food intake and food conversion (FC) were determined at 3 and 6 weeks of age. Abdominal fat deposition (AFD), carcase yield, carcase fat and protein and nitrogen retention were determined at 6 weeks of age. During the starter period chicks were given a 231 g/kg crude protein (CP) diet and a low protein diet supplemented with synthetic amino acid, a: to National Research Council recommendations, b: to the concentration of the control diet, and c: in agreement with the pattern of body composition. Glutamic acid and glycine were added to some diets as sources of non‐essential amino acids (NEAA). All diets contained 12.62 MJ metabolisable energy (AME_n)/kg. The diets administered between 3 and 6 weeks were comparable to the starter diets, except that they contained more AME_n (12.85 MJ/kg) and less protein.

3. Performance equal to that of high protein controls was obtained with birds fed a low protein diet supplemented with synthetic essential and NEAA to the amounts in the control diet or based on the amino acid profile of body protein. This was not achieved with low protein diets supplemented with synthetic amino acids to the amounts recommended by NRC.

4. Without altering performances, the efficiency of protein utilisation of birds fed on low protein diets was superior to that of birds fed on the commercial control diet and their nitrogen excretion was reduced by 26%. The percentage carcase yield and protein was unaffected by the dietary regimen but carcase fat content and AFD increased as the protein content of the diet decreased.

5. These results show that it is possible to obtain the same performances with low protein diets supplemented with synthetic amino acids, using an ideal amino acid balance. However, low protein diets result in a higher carcase fat content.     

Requirement of the hen for sulphur‐containing amino acids

1. The sulphur amino acid requirements of White Leghorn‐type laying hens were determined in two 52‐week experiments using diets based on maize and soyabean meal providing from 5.0 to 6.5 g sulphur amino acids/kg, 12.35 MJ ME/kg and 8.6 to 8.8 g lysine/kg. There were six replicates of 15 individually‐caged hens each per treatment.

2. A requirement of approximately 775 to 800 mg sulphur amino acids /hen d, of which about 390 to 440 mg was methionine, was found for a maximum of 80 to 83 eggs/100 hen d. There were indications that the requirement for maximum egg production was less than that for maximum efficiency of food utilisation.

3. Diets containing 138 g protein/kg supplemented with methionine and lysine supported production and food utilisation as effectively as a diet containing 167 g protein/kg.     

Effects of dietary sulphur‐containing amino acids on performance and breast meat deposition of broiler chicks during the growing and finishing phases

1. Two growth trials were performed to measure the effects of dietary methionine and cystine (SAA) on growth rate, food conversion efficiency and breast meat deposition in male broilers.

2. In experiment 1, broilers were grown on 6 experimental diets covering a range from 6.9 to 9.6 g SAA/kg. The diets were fed from 15 to 33 d of age. Similarly, in experiment 2, 6 diets containing 6.0 to 8.5 g SAA/kg were fed to finishing broilers 33 to 43 d of age. In each experiment 60 birds per treatment were processed, and carcase yield and breast meat percentage were determined.

3. Significant responses in weight gain, efficiency of food conversion and breast meat percentage were detected, which could be described well by exponential regression curves. Dietary SAA requirements to obtain maximum efficiency of food utilisation and maximum breast meat deposition were estimated to be about 9.0 g/kg from 15 to 33 d of age, and about 8.0 g/kg from 33 to 43 d of age.

4. Economic aspects were considered to calculate optimum SAA specifications from the results. In both trials, the dietary optimum of SAA was found to be higher for birds to be further processed than for birds to be marketed as whole carcases.     

Is the kafirin profile capable of modulating the ileal digestibility of amino acids in a soybean meal-sorghum diet fed to pigs?

The effects of kafirins on protein and amino acid ileal digestibility have not been evaluated in vivo in pigs. The aim of this study was to determine the effects of protein profile on apparent ileal digestibility (AID) of amino acids. We used a sorghum hybrid with low tannin content (<0.5%). The same hybrid was harvested from 2 different plots with different kafirin profile. Sorghum with greater content of total kafirins had less content of γ- and α1-kafirins and higher content of β- and α2-kafirins than that with lower content of total kafirins. Two sorghum-soybean meal (SBM) diets were formulated: 1) low kafirin (LK) content (32.2 g/kg) and 2) high kafirin (HK) content (48.1 g/kg). A control diet (maize-SBM) and a reference SBM-diet were also prepared. The reference diet was fed to all pigs following the experimental period and was used to estimate the AID of cereals by the difference method. “T” cannulas were fixed in the distal ileum of 18 barrows (6 by treatment), divided into 2 groups of 9 pigs. The pigs were fed 2.5 times their maintenance requirement of digestible energy (110 kcal/kg BW^0.75). The AID of dry matter, protein, amino acids, and energy of the experimental diets was measured; the AID of cereals (maize, LK sorghum and HK sorghum) was estimated by the difference method. The maize-SBM diet was more digestible than the sorghum-SBM diets, only with respect to valine (P < 0.05). The AID of valine in the maize-SBM diet was higher than that in sorghum-SBM diets. The changes in kafirin profile between the diets only affected the AID of threonine (P < 0.01), which decreased by 9.5 percentage units in LK diet compared with HK diet. Regarding the AID of cereals, maize exhibited greater AID than sorghum, with respect to valine (P < 0.01) and serine (P < 0.10). A comparison of sorghum with LK and HK content showed that the AID of threonine and serine increased by 50.5 (P < 0.001) and 19.2 percentage units (P < 0.05) in the latter, respectively. The higher content of γ-kafirins in LK sorghum negatively affected threonine and serine digestibility, implying that the AID of amino acids is affected more by the profile than the content of kafirins.     

Comparative utilisation of sulphur‐containing amino acids by genetically lean or fat chickens

1. Genetically lean (LL) or fat (FL) male chickens were fed from 28 to 47 days of age on 5 experimental diets differing by their methionine + cystine content (5.4, 5.8, 6.2, 6.6 and 7.0 g/kg, respectively).

2. Growth rate of LL chickens was reduced by the lower sulphur‐containing amino acid (SAA) concentrations whereas that of FL was not modified.

3. LL chickens exhibited a larger feather protein gain than FL, which was stimulated by SAA intake.

4. SAA retention, when plotted against SAA consumption, was always greater in LL than in FL.

5. Large differences were observed between genotypes for plasma‐free amino acids. Lysine, glutamic acid, histidine and serine were found at significantly higher concentrations in LL birds. Branched amino acids, aromatic amino acids, SAA and arginine were found at higher concentrations in FL. No differences were observed for aspartic acid, glycine, alanine and total amino acids. Methionine supplementation decreased free amino acid concentrations, with the exceptions of arginine and leucine.

6. It is concluded that lean chickens require a higher dietary concentration of SAA than FL. This is mainly caused by their lower food consumption and their greater feather synthesis. However, LL use SAA more efficiently than FL.     

A formal method of determining the dietary amino acid requirements of laying‐type pullets during their growing period

1. The amino acid requirements of laying type pullets during the growing period can be estimated by measuring the growth of different components of the body and making use of nutritional constants that define the amount of each amino acid that is required for the production of the tissues being formed.

2. In this experiment, carcase analyses of each of three breeds of pullets were conducted at weekly intervals throughout the growth of the pullets, to 18 weeks of age. Measurements were made of body weight, gut‐fill and feather weight, and chemical analyses consisted of water, protein, lipid and ash measurements of both the body and the feathers. Each age group comprised 10 birds of each breed.

3. Gompertz functions accurately estimated the growth of both body protein and feather protein, to 18 weeks of age, from which the rate of growth of these two components of the body could be estimated. The mature weight of pullets was overestimated by the Gompertz growth curve, which may indicate that a pullet ceases to increase in body protein content once sexual maturity has been reached.

4. Using allometric relationships between the chemical components of the body and of feathers, all the components of growth could be estimated from the growth of body protein and feather protein. These components were then added together to determine the growth rate of the body as a whole.

5. The daily amino acid requirements for 4 functions were calculated, namely, those for the maintenance of body protein and feather protein, and for the gain in body protein and feather protein. These requirements were then summed to determine the requirement of pullets on each day of the growing period.

6. Using the ‘effective energy’ system, the amount of energy required by these pullets was calculated for each day of the growing period, from which the desired daily food intake of the pullets could be predicted. By dividing the amino acid requirement by this daily food intake it was possible to determine the concentration of amino acids that would be needed in the diet in order to meet the requirements of a pullet.

7. The results indicate that the ratio between the requirement for lysine and for methionine and cysteine changes dramatically during the growing period, negating the concept of a fixed ratio between all the amino acids during growth.

8. The above process is the first step in determining the optimal feeding programme for a population of pullets of a given genotype. The constraining effects, of the diet being offered and of the environment in which the pullets are housed, on the food intake and growth rate of each pullet have to be estimated, and such a theory can then be expanded to include all the individuals in the population. Only by the use: of simulation models can all these constraining effects be considered simultaneously.     

The replacement of some of the soybean meal by the first‐limiting amino acids in practical broiler diets

1. Four trials were carried out with broilers from 5 to 9 weeks of age in order to determine the effect of reducing dietary protein concentration, with and without special supplementations of methionine and lysine, on the amount of carcass fat.

2. In all trials fat deposition increased progressively as the protein concentrations of well‐balanced standard finisher diets were lowered by replacing soybean meal with sorghum grains (milo).

3. The increased degree of fatness was the result of graded increases in food consumption, and consequent decreases in food utilisation, caused by inadequate dietary protein.

4. In three out of four trials the above negative trends could be partly or completely reversed by special supplementations with methionine and lysine in amounts to restore the dietary concentration of these first‐limiting amino acids to those of the control diets.

5. It appears that broilers overeat in a compensatory attempt to obtain the limiting amino acids required for optimal growth rate, as long as the deficiency is not severe enough to cause an amino acid imbalance.     

Responses of laying hens to a low‐protein diet supplemented with essential amino acids,l‐glutamic acid and/or intact protein

1. Three sequential experiments, each lasting 8 weeks, were carried out on 576 singly‐caged light hybrids.

2. In experiment 1 egg production was 84% using a conventional control diet, 61% with a basal low‐protein diet, and 79% with the basal diet supplemented with 10 essential amino acids + L‐glutamic acid (GA).

3. In experiment 2 supplementation with lysine and methionine (L + M) alone increased egg production significantly from 54 to 72%, compared with 83% with the conventional diet.

4. In experiment 3 egg production was 55% with the basal diet, 71% with the basal diet + L + M, 75% with a diet containing 141 g protein/kg + L + M, and 73% with the conventional diet.

5. In all three experiments supplementation with GA alone either gave no significant response or a depression in production.

6. Daily intakes of 1.24 g nitrogen as non‐essential amino acids and 13 to 14 g total crude protein per bird resulted in good egg production. Supplementation of the basal diet with L + M resulted in a daily intake of 413 mg methionine/bird day which was considered adequate, and a daily intake of 710 mg lysine which was considered slightly inadequate.     

The egg‐laying response of the domestic hen to variation in dietary calcium

1. Eight diets (1 to 8) containing respectively 36.8, 30.9, 19.6, 9.7, 5.5, 1.9, 0.96 and 0.48 g of calcium/kg food were each fed for 11 weeks to 24 individually‐caged laying hens (Gallus domesticus) aged 24 weeks. After the experimental period, all birds were returned to a normal diet (34.9 g calcium/kg).

2. Food consumption and egg production decreased as dietary calcium decreased. Shell weight was unaffected on diets 1 and 2; on diet 3 there was slight reduction of shell weight and on diets 4 to 8 the reduction was marked. The proportion of calcium in the shell was affected particularly on diets 7 and 8, though those from diet 5 also showed a decreased shell calcium.

3. The values for calcium intake and calcium loss in the egg showed that, generally, birds restricted calcium loss to less than intake. Only on the very low concentrations of calcium (diets 6, 7 and 8) did output appear to exceed input.

4. The main mechanism for controlling calcium loss involves the regulation of the number of eggs produced, i.e. the number of ovulations. Alterations in shell quality are of less importance with respect to calcium balance, although shell strength was impaired on the more restrictive diets (5 to 8).     

Is dietary choice important to animal welfare?

Scientific interest in farm animal welfare has grown rapidly in recent years because consumers increasingly demand that farm animals are reared, transported, and slaughtered in a humane way. Additionally, nutrition emerges as an important aspect of welfare since in most codes of recommendations for the welfare of animals, adequate nutrition is one of the primary requirements to be satisfied. We submit that in many cases domestic animals are provided with diets that, even when abundant and nutritious, are not necessarily adequate to foster the welfare of animals. The monotonous diets fed in confinement (total mixed rations) and on pasture (monocultures) often contain excesses of nutrients, nutrient imbalances, and toxins that adversely influence animal welfare. How much of any food an animal can eat will depend on the other foods it consumes, because at the biochemical level, nutrients and toxins interact one with another—nutrients with nutrients, nutrients with toxins, and toxins with toxins. Food intake and preference also depend on differences in how individual animals are built morphologically and how they function physiologically, and marked variation is common even among closely related animals relative to the needs for nutrients and tolerance to toxins. An integral part of an animal's ability to meet its particular nutritional requirements and consume substances that improve health depends on having a variety of foods available so each animal can select a diet that best meets its homeostatic needs. Food choice may also offer animals a means to cope with toxins, as certain food combinations have the potential to ameliorate the negative effects of toxins. We suggest that the availability of alternatives may not only contribute to maintain homeostasis but also reduce levels of stress. Thus, food choice is necessary for individual animals to have freedom to express their normal behaviors. We contend this freedom enables the uniqueness of individuals to be manifest, thereby promoting animal welfare and performance and increasing profitability of the people who manage animals.     

Standardized ileal digestibility of amino acids in soybean meal fed to non-pregnant and pregnant sowsOA

Background Two studies were designed to determine standard ileal crude protein(CP) and amino acid(AA) digestibility of soybean meal(SBM) from different origins fed to non-pregnant and pregnant sows. Seven solvent-extracted SBMs from soybeans produced in the USA, Brazil, and China were selected. In Exp. 1, eight different diets were created: a nitrogen(N)-free diet and 7 experimental diets containing SBM from different origins as the only N source. Eight non-pregnant, multiparous sows were arrang...     

Effects of dietary enrichment with n–3 fatty acids on the quality of raw and processed breast meat of high and low growth rate chickens

1. The enrichment of raw poultry meat with n–3 fatty acids (n–3 FA) has been investigated in detail, particularly in high growth rate genotype standard broiler chickens, whereas low growth rate genotype Label Rouge chickens have received less attention. With the increased development of processed poultry products, it is necessary to ensure that the nutritional and sensory quality of meat enriched with n–3 FA is not affected by processing.

2. Two experiments were undertaken for this purpose. In the first experiment, 696 male Ross 708 chickens were reared under standard conditions, and in the second, 750 male JA 657 chickens were reared under Label Rouge conditions. All birds received the same starting and growing diets containing palm and soya oils in each experiment. Birds were distributed into three groups from 21 or 57 d of age for standard and Label Rouge chickens, respectively, and given a control, linseed oil or extruded linseed diet. Diets were also supplemented with vitamin E (100–200 mg/kg). Birds were slaughtered at 56 or 84 d of age for standard and Label Rouge chickens, respectively. A total amount of 60 kg of breast meat from each group was processed into white cured-cooked meat.

3. The dietary treatment had no effect on the growth performance of chickens or meat yield. The use of extruded linseed or linseed oil only decreased the carcass fatness of the standard chickens but had no effect on the carcass fatness of Label Rouge chickens. The nutritional quality of raw and cured-cooked meat was improved (increased concentration of n–3 FA), whereas the technological quality of the meat (pH, juice loss after cold storage, susceptibility to oxidation, colour, processing yield and shear force value) and sensory quality of the processed products were not or slightly affected.

4. Linked to lower breast yield, to lower lipid content in breast meat and to higher slaughter age, Label Rouge chickens seemed to be less efficient for n–3 FA deposition in breast muscles than standard chickens.     

Limited evidence for trans-generational effects of maternal dietary supplementation with ω-3 fatty acids on immunity in broiler chickens

The aim of the present study was to investigate whether the immune response of broiler chickens is modulated by including different omega-3 (ω-3) polyunsaturated fatty acids (PUFAs) in the maternal diet. Broiler breeder hens (n = 120 birds per group) were fed one of four diets, differing in the ratios of n-6:n-3 PUFAs and eicosapentaenoic acid (EPA):docosahexaenoic acid (DHA). At 28 weeks of age, the eggs produced were incubated to obtain 720 chicks (n = 180 per group). All broiler chicks were fed a control diet and were vaccinated against Newcastle disease virus (NDV). Blood samples were taken at different time points after immunisation with human serum albumin (HuSA) in Freund's adjuvant to determine the acute phase response, antibody response and cytokine production. Addition of EPA to the maternal diet was associated with greater ovotransferrin concentrations post-immunisation, compared to other groups. Altering the ratios of n-6:n-3 PUFA or EPA:DHA in the maternal diet did not affect the offspring in terms of production of caeruloplasmin, α₁-acid glycoprotein, interleukin (IL)-1β, IL-6, IL-12 or tumour necrosis factor (TNF)-α. Dietary manipulation of the maternal diet did not influence the specific antibody response to HuSA or NDV, nor did it alter the levels of natural antibody binding to keyhole limpet haemocyanin in the offspring. Thus, maternal supplementation with n-3 PUFAs played a minor role in perinatal programming of the immune response of broiler chickens.     

Comparative standardized ileal amino acid digestibility and metabolizable energy contents of main feed ingredients for growing pigs when adding dietary β-mannanase

The present study was conducted to test whether the dietary supplementation of β-mannanase affects amino acids (AA) digestibility, metabolizable energy (ME) contents of corn, wheat, soybean meal, distillers dried grains with solubles, and palm kernel meal (PKM), nutrient digestibility, and growth performance of pigs. In Exp. 1, 22 cannulated pigs were used for 10 dietary treatments including 5 feed ingredients and 2 β-mannanase concentrations (0 and 0.5 g/kg of the diet) in 6 periods in an incomplete Latin square design to determine the AA and energy digestibility. In Exp. 2, 200 growing pigs were randomly allotted to 4 treatments with 2 nutrient levels (high and low) and 2 concentrations of β-mannanase (2 × 2 factorial arrangement) in 2 phases (phase 1, d 0 to 21; and phase 2, d 22 to 42). In Exp. 1, β-mannanase increased the mean standardized ileal digestibility (SID) of AA in all feed ingredients. The amount of digestible energy was increased (P < 0.05) in β-mannanase-treated PKM. Pigs fed β-mannanase showed a greater (P < 0.05) digestibility of gross energy (GE). The feed-to-gain (F:G) ratio was improved (P < 0.01) in pigs fed high-nutrient diets. Pigs fed β-mannanase in the diets had greater (P < 0.05) average daily gain and F:G. In phase 2, the concentration of fecal ammonia was decreased (P < 0.05) in pigs fed β-mannanase. Considering the 2 experiments, it can be concluded that β-mannanase increases the SID of AA, which has to be considered in balancing the rations.     

Erratum to: Effects of feeding different dietary protein and energy levels of the performance of 12−15-month-old buffalo calves

Tropical Animal Health and Production -     

Absence of effects of dietary α‐tocopherol on egg yolk pigmentation

1. Three experiments were carried out in which yolk colour and carotenoid content were measured in hens fed diets containing soyabean oil or tallow and supplemented with 0, 10, 20, 40, 80, 160 or 320 mg tocopheryl acetate.

2. Fat type had no consistent effect on yolk carotenoid content but yolk α‐tocopherol concentrations were lower with the soyabean oil diet.

3. Yolk concentrations of all carotenoids measured and yolk colour were unaffected by dietary α‐tocopherol concentration.     

Effects of ＂Bioactive＂ amino acids leucine, glutamate, arginine and tryptophan on feed intake and mlRNA expression of relative neuropeptides in broiler chicks

Feed intake control is vital to ensuring optimal nutrition and achieving full potential for growth and development in poultry. The aim of the present study was to investigate the effects of L-leucine, L-glutamate, L-tryptophan and L-arginine on feed intake and the mRNA expression levels of hypothalamic Neuropeptide involved in feed intake regulation in broiler chicks. Leucine, glutamate, tryptophan or arginine was intra-cerebroventricularly (ICV) administrated to 4d-old broiler chicks respectively and the feed intake were recorded at various time points. Quantitative PCR was performed to determine the hypothalamic mRNA expression levels of Neuropeptide Y (NPY), agouti related protein (AgRP), pro-opiomelanocortin (POMC), melanocortin receptor 4 (MC4R) and corticotrophin releasing factor (CRF). Our results showed that ICV administration of L-leucine (0.15 or 1.5 μmol) significantly (P<0.05) increased feed intake up to 2 h post-administration period and elevated both hypothalamic NPY and AgRP mRNA expression levels. In contrast, ICV administration of L-glutamate (1.6μmol) significantly (P<0.05) decreased feed intake 0.25, 0.5 and 2 h post-injection, and increased hypothalamic CRF and MC4R mRNA expression levels. Meanwhile, both L-tryptophan (10 or 100μg) and L-arginine (20 or 200μg) had no significant effect on feed intake. These findings suggested that L-leucine and L-glutamate could act within the hypothalamus to influence food intake, and that both orexigenic and anorexigenic Neuropeptide genes might contribute directly to these effects.     

Comparative responses of genetically lean and fat chickens to lysine,arginine and non‐essential amino acid supply. II. plasma amino acid responses

1. Three experiments performed to study the effects of amino acid imbalances on the growth of genetically lean (LL) and fat (FL) male chickens from 28 to 42 d of age were described by Leclercq et al. (1994). The plasma amino acid concentrations of birds on selected treatments from that paper are reported here. In experiment 1, three dietary concentrations of digestible lysine were compared (4.75, 6.75 and 7.75 g/kg). In experiment 2, two dietary concentrations of digestible arginine were compared (6.53 and 10.00 g/kg). In experiment 3, three diets were compared: a high‐protein diet (189 g CP/kg), a low‐protein diet containing added essential amino acids (144 g CP/kg), and this low‐protein diet supplemented with 40 g/kg of non‐essential amino acids (NEAA; glutamic and aspartic acids).

2. The present results are compared with two earlier reports on the same genotypes. The LL consistently had lower plasma concentrations of me‐thionine, cystine, phenlyalanine, isoleucine and valine, and higher concentrations of histidine, than the FL chickens. In 4 of 5 experiments, LL leucine concentrations were lower, and glutamic acid, tyrosine, glutamine and alanine were higher, than in the FL. The other amino acids measured; arginine, lysine, aspartic acid, glycine and serine, exhibited variable responses among the experiments.

3. When the limiting essential amino acids, lysine and arginine, were added to a deficient diet, the plasma concentration of the supplemented amino acid increased while the others remained constant or decreased.

4. When glutamic and aspartic acids were added to the low protein diet, plasma amino acid responses were similar to those of adding a limiting amino acid to a deficient diet, except that alanine exhibited a dramatic increase.

5. Although there were genotype by diet interactions for several amino acids, the interactions were caused by differences in the degree of the responses, not in their direction.

6. These results suggest that the FL and LL genotypes do not utilise various amino acids with the same efficiency and, as a consequence, the ideal profile of dietary amino acids should not be the same for both lines. The results support the hypothesis that selection for fatness and leanness changed the amino acid requirements independently of the: effects of food intake.