Apportioning protein requirements for maintenance v. growth for blue-breasted quail (Excalfactoria chinensis) from 7 to 21 days of age

The aim of this study was to investigate protein requirements for the maintenance and growth of blue-breasted quail (Excalfactoria chinensis) from 7 to 21 days of age. A total of 180 quails, 7 days old, were randomly assigned to 36 cages and for 2 weeks were fed diets with a metabolisable energy concentration of 12.13 MJ/kg and a dietary CP concentration of 125, 150, 175, 200, 225 or 250 g/kg. The average BW per cage and the feed intake per cage were recorded daily. The results showed that quails fed 125 g/kg CP could not maintain their BW and had negative feed efficiency. There were linear and quadratic relationships between CP level and response criteria, including BW, weight gain, feed intake, feed efficiency, final body nitrogen mass and body nitrogen accretion (P<0.05). The dietary CP requirements, as calculated using a one-slope quadratic broken-line model, were 211 and 202 g/kg according to weight gain and feed efficiency, respectively. The regression equations, on the basis of metabolic BW, of daily weight gain on daily protein intake according to the model were Y=0.137-2.128(0.113-X) if X<0.113 and Y=0.137 if X>or=0.113 (R2=0.96, P<0.001), which meant that the protein requirement for maintenance was 0.049 times the metabolic BW and that to gain 1 g weight quails needed to ingest an extra 0.47 g protein after the maintenance requirement was satisfied. The regression equations, on the basis of metabolic BW, of daily body nitrogen accretion on daily protein intake according to the model were Y=5.667-76.700(0.119-X) if X<0.119 and Y=5.667 if X>or=0.119 (R2=0.95, P<0.001), which meant that quails had to receive an amount of protein equal to their metabolic BW multiplied by 0.045 to satisfy the requirement for maintenance and then ingest an extra 13 g protein to accrete 1 g body nitrogen. In conclusion, growth or protein accretion rates should be regulated according to dietary CP for specific experimental purposes via apportioning protein requirements for maintenance v. growth.     

Effects of the dietary protein content and the feeding level on protein and energy metabolism in Iberian pigs growing from 50 to 100 kg body weight

Nutritional requirements of the Iberian pig, a slow-growing, obese porcine breed, are not well defined and seem to differ from those of conventional or high-performing pigs. The effects of the dietary protein content and the feeding level on the utilisation of metabolisable energy (ME) and the rates of gain, protein, and fat deposition were studied with 81 Iberian castrates growing from 50 to 100 kg body weight (BW) by using the comparative slaughter technique. The animals were fed 4 diets providing 145, 120, 95, and 70 g ideal crude protein (CP) per kg dry matter (DM), and containing 13.94, 14.29, 14.56, and 14.83 MJ ME per kg DM, respectively. Three levels of feeding were evaluated: 0.60, 0.80, and 0.95 × ad libitum intake. Growth rate increased (linear and quadratic, P < 0.001) as the dietary ideal CP content decreased. It also increased with the feeding level (linear, P < 0.001; quadratic, P < 0.05). Gain:feed and gain:ME intake improved by decreasing the ideal CP content in the diet (linear, P < 0.001 and P < 0.05, respectively; quadratic P < 0.001 for both variables). Increasing the feeding level improved linearly gain:feed and gain:ME intake ( P < 0.001). Protein deposition (PD):ME intake ranged between 1.23 and 1.44 g/MJ, and it showed a tendency to reach the maximum value when the diet providing 95 g ideal CP per kg DM was fed (quadratic, P = 0.078). When this diet was offered at 0.95 × ad libitum, PD reached a maximum value of 71 g/day. This dietary treatment resulted in average values for average daily gain and retained energy (RE) of 854 g/day and 21.4 MJ/day, respectively. The average rate of gain was 19.93 g/MJ increase in ME intake, equivalent to an energy cost of 50.2 kJ ME per g gain, irrespective of the dietary ideal CP content. Also, the overall marginal efficiency of protein deposition (ΔPD:ΔME; g/MJ) was 1.34. Increasing the feeding level led to increases in PD (linear, P <  0.001) and RE (linear, P <  0.001; quadratic, P <  0.01) irrespective of the dietary ideal CP concentrations. Between 50 and 100 kg BW, the chemical composition of 1 kg gain averaged 78, 592, 28.7, and 284 g for CP, fat, ash, and water respectively. The net efficiency of use of ME for growth ( k_g) and the maintenance energy requirements were 0.606 and 396 kJ/kg BW ^0.75 per day, respectively. The results support earlier findings that the genotype has marked effects on protein and energy metabolism of growing pigs and underline important compositional differences of the Iberian pig compared with conventional or modern porcine genotypes.     

Effects of dietary sulfur amino acids and crude protein on the performance of finishing broilers

The effects of different combinations of dietary methionine+cystine (Met+Cys) and dietary crude protein (CP) in finishing broilers were investigated in two growth studies. In Exp. 1, male broilers 29 to 42 days of age were fed 18 diets containing 16.9%, 18.7%, or 20.4% CP with six levels of Met+Cys within each protein level. Similarly, in Exp. 2 another 12 diets containing either 18.0 or 21.5% CP were fed to male broilers 29 to 48 days of age.

In general, the Met+Cys requirement for optimum feed conversion was higher than for maximum growth. In both experiments, between 0.80% and 0.85% methionine+cystine optimized feed conversion. These dietary levels were valid for a 13.05 MJ ME/kg diet fed to broilers growing from 1.2 kg to 2.2 kg (Exp. 1), or for a 13.60 MJ ME/kg diet fed to broilers growing from 1.3 kg to 3.0 kg (Exp. 2).

The Met+Cys requirement was not consistently affected by the dietary CP content in Exp. 1. In Exp. 2, increasing dietary CP from 18.0% to 21.5% tended to increase the Met+Cys requirement for optimum feed conversion.

A dietary CP level of 18.0% to 18.7% supported performance and carcass fat deposition equal to diets containing 20.4% or 21.5% CP, respectively, when the sulfur amino acid content was adequate.     

Dietary essential oils improve feed efficiency and hepatic antioxidant content of broiler chickens

The aim of this study was to test the hypothesis of an improved growth, dietary nutrient availability and overall health of broiler chickens reared on recycled litter when fed a standardised combination of essential oils (EO; carvacrol, cinnamaldehyde and capsicum oleoresin). To assess the effect of dietary treatments, feed intake, weight gain, feed efficiency, availability of dietary nutrients and energy, villus morphometry, excreta sialic acid concentration, hepatic antioxidants and serum amyloid A (SAA) when fed to broiler chickens were evaluated. Counts of Eimeria spp. oocysts were also determined in excreta samples. Four experimental diets were offered, including two basal control diets based on either wheat or maize that contained 215 g CP/kg and 12.13 MJ/kg metabolisable energy and another two diets using the basal control diets supplemented with the EO combination at 100 mg/kg diet. Each diet was fed to eight floor pens, containing two birds each, following randomisation. Birds fed the EO-supplemented diets had an improved (P<0.05) feed conversion ratio (FCR). Birds fed maize-based diet had an improved daily weight gain and FCR (P<0.05) compared with wheat-fed birds. Wheat-based diet tended (P=0.056) to have greater N-corrected apparent metabolisable energy and had greater fat retention coefficient (P<0.05) compared with maize-based diets. No differences (P>0.05) were observed in villus morphometry, sialic acid secretion, number of oocysts and SAA. Feeding the EO improved (P<0.05) the retention of dietary Ca and Na. Compared with maize, feeding wheat-based diets improved the retention coefficients for Ca, P and Na (P<0.05). Feeding dietary EO improved (P<0.05) the concentrations of the hepatic antioxidants, including carotene, coenzyme Q₁₀ and total vitamin E. The hepatic concentration of carotene of the maize-fed birds was 55.6% greater (P<0.05) compared with the wheat-fed birds. These results demonstrated that the addition of a standardised combination of EO in wheat- and maize-based diets provided benefits in terms of feed efficiency, mineral retention and antioxidant status of the birds when reared on recycled litter.     

Metabolizable energy requirements for maintenance and growth of Awassi lambs

Twenty four Awassi lambs (mean BW 24.4 kg) were used in a two periods experiment to measure maintenance (zero growth) and growth requirements of metabolizable energy (ME). During the pre-treatment period (period 1, 3 weeks) all lambs were maintained at a constant level of feed intake (2% BW). During the treatment period (period 2, 10 weeks) the lambs were divided into four equal groups and fed different amounts (2, 3, 4 and 5% of BW). Six additional lambs of similar BW and age were killed at the beginning of the experiment to compare final empty body weight (FEBW) with initial body weight (IBW). Twelve lambs, divided into four equal groups were fed the experimental diet in the same amounts as in the growth experiment (period 2) to determine the digestibility of energy.

Energy requirement for maintenance (EM) was measured by both constant weight technique, using data collected during period 1, and regression technique by regressing ME intake on body weight gain (BWG) and empty body weight gain (EBWG). EM measured during the constant weight period (pre-treatment) and overall experimental period (pre-treatment plus treatment periods) were 0.482 and 0.466 MJ of ME per kg M^0.75 per day. Predicted energy requirements for growth (Eg) calculated from equations derived during the treatment period were 0.433, 0.623, 0.782, 0.910 and 1.007 (MJ per kg M^0.75 per day) for the growth rates 50, 100, 150, 200, and 250 (g per day) respectively. It is concluded to be more appropriate to use the values derived during the overall experimental period for maintenance and the overall treatment period for growth as they are most applicable to production situations.     

Dietary protein or energy restriction influences age and weight at puberty in ewe lambs

The working hypothesis was that restricted protein content in diets of prepubertal ewe lambs would delay time of onset of puberty to a greater extent than restricted energy content. Restriction of dietary protein (metabolizable protein, MP) or energy (ME) intake on age and weight at puberty was studied in ewe lambs in two experiments. In Experiment 1, 85 crossbred ewe lambs were assigned by weight to one of five dietary treatment groups: control (CTL; 18 mg ME day⁻¹ and 173 g MP day⁻¹); energy restricted (ER; 10.2 mg ME day⁻¹ and 96 g MP day⁻¹); protein restricted (PR; 11 mg ME day⁻¹ and 66 g MP day⁻¹); ER for 9 weeks then switched to CTL (ER/CTL); PR for 9 weeks then switched to CTL (PR/CTL). Ewe lambs were weighed biweekly, bled weekly, and serum was assayed for progesterone to determine time of puberty. Average age at puberty differed among lambs fed the various diets (P < 0.01). Ewe lambs in the CTL group were younger and weighed more at puberty. Lambs fed diets restricted in protein or energy content were similar in age at puberty. Dietary switching, ER/CTL and PR/CTL, affected body weight and gain (P < 0.05), but did not result in changed age at puberty compared with lambs fed ER or PR diets. In Experiment 2, two breed types (maternal type and meat type) were used to compare responses of dietary protein restriction to dietary energy restriction. In Experiment 2, lambs (n = 60) were assigned to either the CTL, PR or ER diets. Lambs in the CTL group gained more weight than lambs fed the PR diet and lambs fed the PR diet gained more weight than lambs fed the ER diet (P < 0.05). Diet affected age (P < 0.001), but not weight at puberty (P = 0.13). Dietary energy and protein restriction influenced age at puberty in ewe lambs with energy restriction having a greater influence on delaying onset of puberty than protein restriction. Realimentation did not overcome effects of previous feed restriction by inducing an earlier age at puberty than ewe lambs fed the ER or PR diet throughout the experimental period. Body weight gain prepuberty is more important than type of dietary restriction (protein or energy) with regard to impacting age at puberty. We, therefore, reject the working hypothesis that dietary protein restriction prepuberty would have a greater impact in delaying onset of puberty than dietary energy restriction.     

Interaction and imbalance between indispensable amino acids in young piglets

Lowering protein level in diets for piglets urge to have knowledge on the piglet’s requirements for essential amino acids (AA) and their interactions. The present studies aimed to determine the interaction between the dietary level of valine (Val) and tryptophan (Trp) and the effect of AA imbalance at two levels of dietary Val on the growth performance of post-weaning piglets. In Experiment 1 (duration 4 weeks), the effects of supplementation of free l-Val (1.0 g/kg) and/or l-Trp (0.5 g/kg) in a low-CP diet (CP 17.7%), marginal in Trp and Val, was studied in a 2×2 factorial design and using an additional reference treatment (CP 19.5%). In Experiment 2 (duration 5 weeks), the influence of a stepwise increase in excess supply of isoleucine (Ile), histidine (His) and leucine (Leu), up to 10, 10% and 30% relative to their requirement values respectively, was evaluated at 60% or 70% standardized ileal digestible (SID) Val relative to SID lysine, using a 3×2 factorial design. In Experiment 1, over the whole experimental period, feed intake (FI) was affected by dietary Trp level (P<0.05) and feed conversion ratio (FCR) by both the level of Trp and Val in the diet (both P<0.05). Increasing Trp level increased FI and decreased FCR while increasing dietary Val level reduced FI and increased FCR. For BW gain (BWG), there was an interaction between dietary level of Trp and Val (P<0.05). Valine supplementation decreased BWG using a diet marginal in Trp, whereas it increased BWG when using a Trp sufficient diet. Piglets fed the low-CP diet with adequate levels of Val and Trp showed at least same performance compared to piglets fed the high CP reference diet. In Experiment 2, increasing dietary Val improved FI and BWG (P<0.001) and tended to improve FCR. Dietary AA excess for Ile, His and Leu reduced FI and BWG (P<0.05) and only affected FCR (P<0.01) in the 1^st week of the study. Dietary level of Val and AA excess did not show interactive effects, except for FCR over the final 2 weeks of the study (P<0.05). In conclusion, an interaction exists between dietary supply of Val and Trp on the zootechnical performance of post-weaning piglets and dietary AA excess for Ile, Leu and His, reduces growth performance of piglets in low-protein diets, independent of the dietary level of Val.     

Use of red pepper oil in quail diets and its effect on performance,carcass measurements,intestinal microbiota,antioxidant indices,immunity and blood constituents

Plant-derived additives are used to maintain the health and growth performance of livestock. The use of red pepper oil (RPO) has recently attracted considerable scientific interest mainly due to its potential benefits for animals and humans. The present study was conducted to evaluate the effect of dietary supplementation with RPO on growth performance, carcass measurements, antioxidant status and immunity of growing quails between 1 and 5 weeks of age. A total of 240 growing quails (1-week old) were distributed into 5 equal groups consisting of 48 birds (4 replicates of 12 birds each). The first group was fed a basal diet without RPO (0 g/kg diet), and the second, third, fourth and fifth groups received diets containing RPO (0.4, 0.8, 1.2, 1.6 g/kg diet, respectively). The experiment lasted for 5 weeks. At age of 5 weeks, quails were slaughtered for carcass examinations, microbiological analysis of intestine and to determine blood constituents. Data were statistically analyzed by one-way ANOVA. Quails fed with 0.8 g RPO/kg diet showed 12.14%, 14.4% and 15% improvement in live BW, body weight gain and feed conversion ratio, respectively, compared with the control group. Quails that received diets with 1.2 g RPO consumed more feed than the others during the total period (1 to 5 weeks). Plasma globulin levels were significantly decreased (P = 0.0102), but albumin/globulin ratio was significantly increased (P = 0.0009) in birds fed diets containing RPO (0.4 and 1.2 g/kg) compared with those in the control group. Activity of liver enzymes in the plasma was nonsignificantly decreased in quails supplemented with 0.8 g RPO/kg diet compared with those in the control group. Activities of antioxidant enzymes (glutathione and catalase) in the group fed on diets supplemented with RPO (0.8 g/kg) were significantly higher than those in the control group. The inclusion of RPO (0.8 g/kg diet) in quail diets improved (P < 0.05) plasma lipid profile and also decreased pH of the caecal content (P = 0.0280) compared with those in the control group. The caecal bacterial population, Salmonella spp., coliform and Escherichia coli, were lowered (P < 0.05) in the groups treated with RPO (0.8, 1.2 and 1.6 g/kg) compared with those in the control group. In conclusion, dietary supplementation of RPO (0.8 g/kg) can enhance the performance and antioxidant indices and decrease intestinal pathogens and thus improve the health status of Japanese quail.     

Effects of feed form and energy levels on growth performance,carcass yield and nutrient digestibility in broilers

Feed form is well recognized to improve broiler performance, specially by increasing feed intake (FI). However, when different diet energy levels are used, the results differ in the literature. Therefore, this experiment was conducted to evaluate the influence of feed form and dietary metabolizable energy (ME) levels on broiler performance, carcass yield and on the digestibility of DM, CP, starch and gross energy. In total, 1152 male Cobb 500 broilers were evaluated between 35 and 47 days. The birds were distributed according to a completely randomized design in a 2 × 4 factorial arrangement, consisting of two feed forms (mash or pellet) and four ME levels (12.73, 13.06, 13.40 or 13.73 MJ/kg), totaling eight treatments with eight replicates of 18 birds. Broilers fed the lowest ME level presented the lowest weight gain (WG) and worst feed per unit gain (P < 0.01). Metabolizable energy intake increased (P < 0.01) with progressive increments of ME, which, however, did not affect caloric conversion (CC, P > 0.05). Pelleted diets promoted higher FI, WG, ME intake (P < 0.01) and better feed per unit gain and CC (P < 0.05) compared with mash. In mash diets, increasing dietary ME levels promoted a linear increase in WG (P < 0.01) and reduced feed per unit gain (P ≤ 0.05), but did not affect FI (P > 0.05). In pelleted diets, on the other hand, increasing ME levels linearly reduced FI (P < 0.05) and feed per unit gain (P < 0.01). Broilers fed pelleted diets presented higher abdominal fat deposition than those fed mash (P < 0.05). Increasing ME levels reduced the coefficients of ileal apparent digestibility of DM (P < 0.01) and total starch (P < 0.05) but did not affect the digestibility of other evaluated nutrients. The digestibility of all nutrients was lower when pelleted diets were fed compared with mash. Increasing inert material inclusion in the diets at the expense of soybean oil to reduce dietary ME levels promoted higher pellet durability index values (P < 0.05) and the percentage of fines (P < 0.01). Overall, the results suggest that pelleted diets promote better broiler performance because they increase FI, since the digestibility of dietary fractions is reduced. Chickens consuming low-energy pelleted diets may increase FI to compensate for energy deficit. In contrast, broilers fed mash diets may have reached their maximum intake capacity and did not regulate FI by changing feed energy density. When feeding pelleted diets, dietary energy reduction should be considered to reduce feed costs and to improve the carcass quality of broilers.     

The impact of betaine supplementation in quail diet on growth performance,blood chemistry,and carcass traits

The study aimed to investigate the effect of various doses of betaine supplemented dietary on Japanese quail performance, carcass characteristics, and blood chemistry. Therefore, 400 seven days old Japanese quails were classified randomly into four equal groups. Each group was subdivided into five replicates of 20 birds each. Four rations were formulated using four different betaine levels (0, 0.75, 1.5 and 2.25 g/kg, respectively) for five successive weeks. All groups received feed and clean water ad-libitum. The results of this trial indicated that the feed intake was lowered in groups fed with betaine (p ≤ 0.05) when compared with the control one. The highest weight gain (p ≤ 0.05) was noticed in groups fed diets BS4 (betaine supplementation at the rate of 2.25 g/kg). No difference among groups was observed in body length, shank length, shank diameter, and keel bone length or breast width. Also, the carcass weight and breast yield were highest (p ≤ 0.05) in the group reared on the BS4 diet. In addition, intestinal length and weight were significantly higher (p ≤ 0.05) in groups fed betaine with a concentration of 2.25 g/kg. Fat weight was lower in the group fed BS4 than in the untreated group. Significantly higher values of high-density lipoprotein (p ≤ 0.05) were observed in the group fed BS4. All groups fed a ration containing betaine showed lower levels of liver enzymes such as alanine amino transferase, alkaline phosphatase, and aspartate amino transferase (p ≤ 0.05) and lowered low-density lipoprotein level. The quails fed BS4 had the greatest growth hormones and insulin (p ≤ 0.05) and the lowest thyroxin level. We concluded that dietary betaine supplementation positively impacts Japanese quail growth performance, carcass traits, and blood chemistry.     

Production and composition of Iberian sow's milk and use of milk nutrients by the suckling Iberian piglet

Sixteen purebred Iberian (IB) sows were used in two consecutive trials to determine the efficiency of conversion of sow's milk into piglet body weight (BW) gain and the relationship between milk protein and body protein retention and between milk energy yield and body energy retention in the nursing IB piglet. In each trial, four sows were selected in order to evaluate their milk production, litter growth and nutrient balance measurements, together with four additional sows for milk sampling. Litter size was equalized to six piglets. Daily milk yield (MY) was determined weekly by the weigh-suckle-weigh technique over a 34-day lactation period. Piglets were weighed individually at birth and then weekly from day 5 of lactation. Milk samples were collected on days 5, 12, 19, 26 and 34 post partum. The comparative slaughter procedure was used to determine piglet nutrient and energy retention. One piglet from each litter was slaughtered at birth and four on the morning of day 35. Total MY was on average 5.175 ± 0.157 kg/day. The average chemical composition (g/kg) of the milk was 179 ± 4 dry matter, 53.4 ± 1.0 CP, 58.5 ± 3.8 fat, 10.4 ± 0.3 ash and 56.9 ± 2.3 lactose. Milk gross energy (GE) was 4.626 ± 0.145 MJ/kg. Milk intake per piglet tended to increase in trial 2 (832 v. 893 g/day; P = 0.066). Piglet BW gain contained (g/kg) 172.1 ± 1.3 protein, 151.5 ± 3.5 fat, 41.4 ± 0.6 ash and 635 ± 3 water and 10.127 ± 0.126 MJ GE/kg. Throughout the 34-day nursing period, the piglets grew at an average rate of 168 ± 3 g/day. The ratio of daily piglet BW gain to daily MY was 0.195 ± 0.002 g/g and the gain per MJ milk GE intake was 41.9 ± 0.5 g/MJ. The overall efficiency of protein accretion (g CP gain/g CP milk intake) was low and declined in trial 2 (0.619 v. 0.571; P = 0.016). Nutrient and energy deposition between birth and weaning were 27.4 ± 0.5 g/day protein, 24.2 ± 0.8 g/day fat and 1615 ± 40 kJ/day energy. Piglet energy requirements for maintenance were 404 kJ metabolizable energy (ME)/kg BW0.75. ME was used for growth with a net efficiency of 0.584. These results suggest that poor efficiency in the use of sow's milk nutrients rather than a shortage in milk nutrient supply might explain the low growth rate of the suckling IB piglet.     

Effects of silage from maize crops differing in maturity at harvest,grass silage feed value and concentrate feed level on performance of finishing lambs

The effects of (i) medium and high feed value (MFV and HFV) maize silages and (ii) MFV and HFV grass silages, each in combination with a range of concentrate feed levels, on the performance of finishing lambs were evaluated using 280 Suffolk-X lambs (initial live weight 36.1 kg). The MFV and HFV maize silages represented crops with dry matter (DM) concentrations of 185 and 250 g/kg, respectively, at harvest, and had starch and metabolisable energy (ME) concentrations of 33 and 277 g/kg DM and 9.6 and 11.0 MJ/kg, respectively. HFV and MFV grass silages had DM and ME concentrations of 216 and 294 g/kg and 11.0 and 11.5 MJ/kg DM, respectively. A total of 13 treatments were involved. The four silages were offered ad libitum with daily concentrate supplements of 0.2, 0.5 or 0.8 kg per lamb. A final treatment consisted of concentrate offered ad libitum with 0.5 kg of the HFV grass silage daily. Increasing the feed value of grass silage increased (P < 0.001) forage intake, daily carcass and live weight gains, final live weight and carcass weight. Increasing maize silage feed value tended to increase (P = 0.07) daily carcass gain. Increasing concentrate feed level increased total food and ME intakes, and live weight and carcass gains. There was a significant interaction between silage feed value and the response to concentrate feed level. Relative to the HFV grass silage, the positive linear response to increasing concentrate feed level was greater with lambs offered the MFV grass silage for daily live weight gain (P < 0.001), daily carcass gain (P < 0.01) and final carcass weight (P < 0.01). Relative to the HFV maize silage, there was a greater response to increasing concentrate feed level from lambs offered the MFV maize silage in terms of daily carcass gain (P < 0.05) and daily live weight gain (P = 0.06). Forage type had no significant effect on the response to increased concentrate feed level. Relative to the MFV grass silage supplemented with 0.2 kg concentrate, the potential concentrate-sparing effect of the HFV grass silage, and the MFV and HFV maize silages was 0.41, 0.09 and 0.25 kg daily per lamb, respectively. It is concluded that increasing forage feed value increased forage intake and animal performance, and maize silage can replace MFV grass silage in the diet of finishing lambs as performance was equal to or better (depending on maturity of maize at harvest) than that for MFV grass silage.     

Estimates of individual factors of the tryptophan requirement based on protein and tryptophan accretion responses to increasing tryptophan supply in broiler chickens 8-21 days of age

Ten diets (196 g CP and 13.0 MJ ME(N)/kg) with graded levels of tryptophan (Trp) between 0.9 and 2.7 g/kg were offered ad libitum to Ross broilers from day 8-21 post-hatch. Each diet was allocated to three pens of ten birds each. In addition to growth and feed conversion, the accretions of protein, Trp, fat, and energy were determined by comparative whole body analyses. A sigmoidal function was fitted to the data. Responses to Trp supply were nonlinear and attained plateau values (y(max)) within the studied range of Trp supply. The Y(max) values estimated for BW gain, whole body protein gain, and Trp gain during the 14 days under study were 615, 104, and 0.87 g/bird, respectively. Based on the response in whole body protein gain, the estimated requirement was 1.9 g Trp/kg of diet or 0.15 g Trp/MJ of MEN. Estimates made from the other response criteria were similar to this value. While the protein concentration in gained BW was unaffected by Trp intake (169 g of protein per kg of gained BW), fat and energy concentrations of gained BW increased with increasing Trp supply, approaching plateau values of 146 g fat and 9.8 MJ energy per kg of gained BW. This is supposed to result from feed intake increasing with Trp supplementation. The Trp concentration in gained whole body protein (0.84 g Trp/ 16 g of gained N) was not significantly affected by Trp intake. As long as Trp intake was the limiting factor, 59% of supplemented Trp was transferred to gained whole body protein. During the 14 days of the study, broilers inevitably lost 87 mg Trp. This is equivalent to a daily loss of 30 mg/kg BW or a maintenance requirement of 52 mg/kg BW per day. Data determined for the individual factors may be used for future modelling of broilers' Trp requirement.     

The effect of dietary crude protein level on intake,growth, protein retention and utilization of growing male Saanen kids

The effects of increasing dietary levels of crude protein on growth, feed intake, feed efficiency and composition of gain in male Saanen kids were studied. Four groups of four kids each initially weighing 12.1±0.18 kg and having a weight gain of 195±16 g/d were penned individually and fed for 73 to 124 days up to 25 kg of BW. They were fed chaffed wheat straw (45 g CP/kg DM) which had been molasses sprayed (10%) and pelleted concentrates containing 8.7, 11.7, 14.4 and 17.6% crude protein (CP) on DM basis, the ratio of straw to concentrate being 1:5. Kids were fed controlled to satiation in which case small amounts of the feeds were offered about five times a day as long as the kids wanted to eat. Retention of protein, fat and energy were calculated from their initial and final concentrations in the empty body homogenates of the slaughtered kids. With increasing CP level in the diet, feed intake increased from 448 to 608 g DM/d, weight gain from 94 to 181 g/d, retention of protein from 9.7 to 27.8 g/d, retention of fat from 9.6 to 19.1 g/d and feed efficiency improved from 4.79 to 3.39 kg DM/kg weight gain. Protein composition of gain increased from 103 to 154 g/kg BWG while fat (103–105 g/kg BWG) remained constant. Regression analyses showed that BWG can be optimized at 136 g CP/kg DM and protein retention at 180 g CP/kg DM, whereas, dietary nitrogen was utilized most efficiently at 120 g CP/kg DM. Extrapolated from the regression equations, maintenance N requirement of the kids at zero N-retention and at zero BWG were 0.38 and 0.16 g N/kg W^0.75, respectively. Recommended dietary CP concentrations and maintenance N requirements depend on the traits desired.     

Determination and prediction of the energy content and amino acid digestibility of peanut meals fed to growing pigs

Two experiments were conducted to determine the content of digestible energy (DE) and metabolisable energy (ME) as well as the apparent ileal digestibility (AID) and standardised ileal digestibility (SID) of amino acids in peanut meal (PNM) for growing pigs. In Experiment 1, 78 growing pigs (46.8 ± 2.6 kg) were randomly allotted to 1 of 13 diets, including a corn–soya bean meal basal diet and 12 PNM test diets. In Experiment 2, 12 growing barrows (48.7 ± 2.8 kg) were allotted to one of two 6 × 6 Latin squares. The treatments include a N-free diet and 10 PNM test diets. The results of Experiment 1 showed that the DE and ME differed (p < 0.05) among the 12 PNM samples. On a dry matter basis, the DE and ME content ranged from 14.5 to 16.4 MJ/kg (mean 15.6 MJ/kg) and from 12.7 to 15.5 MJ/kg (mean 13.9 MJ/kg), respectively. The apparent total tract digestibility (ATTD) of gross energy (GE) was 82.2%. The DE of PNM could be precisely predicted by equations including NDF combined with GE or crude protein (CP) with an R² value of 0.91 and 0.92, respectively. For the AID and SID for lysine, the results of Experiment 2 indicated variations among PNM sources ranging from 59.6% to 76.7% and 64.8% to 80.9%, respectively. However, for CP, variations for AID and SID were lower and ranged from 70.2% to 81.9% and 75.7% to 85.6%, respectively. The results indicate that the concentration of lysine was the best single predictor to estimate the digestibility of amino acids. However, further work is needed to investigate the reason for the variation in the digestibility of lysine and avoid processing procedures that are detrimental to lysine digestibility.     

15N-Harnstoffumsatz bei Schafen nach Verabreichung in gelöster Form

Two slaughter experiments were carried out to determine whether the protein content of the diet has an influence upon the efficiency of utilization of ME in fast growing chickens. A normal‐protein diet (NPD, 204 g CP/kg DM; 14.7 MJ ME/kg DM) based on soybean meal as the sole source of protein was given at four different levels of intake (ad libitum or restricted at about 90, 65 and 40% ad lib) to 10‐d‐old animals for 2 weeks. In a parallel experiment the chickens were fed ad libitum a low protein diet (LPD, 66 g CP/kg DM; 15.0 MJ ME/kg DM) based on soybean meal. The intake of metabolizable energy ranged from 1675 to 777 and 1770 to 832 kJ/kgW^0.75 per day for NPD and LPD treatments, respectively. Mean values of energy retention, gross efficiency of energy utilization and energy retained as protein were significantly (P<. 05) lower and heat production (expressed as both kJ/kgW^0.75 per day and kJ/kg body protein content^0.75 per day) was significantly higher (P < .05) for the chickens fed on LPD. These findings support the concept of dietary‐induced thermogenesis in response to reductions in dietary protein concentration. It is concluded that the increased heat production found in the birds fed on the low‐protein diet can be explained by both an increase in energy requirements for maintenance (ME_m) and a sharp decrease in the efficiency of utilization of ME for growth (k₈).     

饲料中棕榈油替代鱼油和豆油对黄颡鱼生长和肌肉脂肪酸组成的影响

为研究不同棕榈油替代水平对黄颡鱼生长性能、肌肉脂肪酸组成、形体指标和肝脏组织结构的影响, 实验采用5组等氮(400 g/kg)等脂(100 g/kg)等能(15.70 MJ/kg)饲料饲喂黄颡鱼[(16.15±0.04) g], 对照饲料以鱼油鲶豆油1鲶2混合为脂肪源, 实验饲料以棕榈油分别替代10、25、40和55 g/kg的混合脂肪源。经过8周的养殖实验, 结果表明棕榈油替代水平对黄颡鱼的摄食量、终末体重、特定生长率、饲料效率和蛋白沉积率未产生显著性的影响(P>0.05), 但是上述指标均呈现先升高后略微下降的趋势, 并在25 g/kg替代组达到最大值。背肌肌肉中亚油酸和n-3HUFA含量随着棕榈油替代水平的上升而显著下降(P<0.05), 但n-3/n-6比值随着棕榈油替代水平的上升而显著上升(P<0.05), 棕榈油替代水平对各组黄颡鱼的肥满度和脏体比未产生显著性的影响(P>0.05), 但是55 g/kg棕榈油替代水平组肝体比显著高于25 g/kg棕榈油添加组(P<0.05), 且55 g/kg棕榈油替代水平组黄颡鱼的肝脏组织出现细胞肿胀, 细胞核移位, 肝血窦和脂肪细胞数量明显增多等不良影响。据上所述: 对于黄颡鱼幼鱼, 棕榈油可以替代25 g/kg的混合脂肪源(鱼油鲶豆油=1鲶2)不影响鱼体生长性能并且在一定程度上改善了背肌肌肉脂肪酸组成。     

Effect of feeding different protein to energy (P/E) ratios on the growth performance and body composition of Oreochromis niloticus fingerlings

This study evaluated the growth performance and body composition of Oreochromis niloticus fingerlings (average initial weight 16.53 ± 0.44 g) fed 9 experimental diets (A, B, C, D, E, F, G, H and I) containing three different levels of protein (26, 31 and 36 g 100 g^?1) at three different gross energy (GE) levels (16, 19 and 22 MJ kg^?1) for a period of 64 days. Significant differences were observed in the feed consumption, body weight gain, specific growth rate (SGR), condition factor (k), feed conversion ratio (FCR), protein efficiency ratio (PER), net protein retention (NPR) and apparent net energy retention (ANER) values of fish when the energy level of diet was increased at different protein levels. The maximum weight gain, SGR and k were observed on diet F containing 36% protein and an energy level of 19 MJ kg^?1 of dry feed with a protein to energy (P/E) ratio of 18.96 (g protein MJ^?1 GE). A further increase in the energy content of the diet (22 MJ kg^?1) at the same protein level (Diet I) did not produce any improvement in the growth performance. Lowering the energy level at the same protein level significantly affected the growth performance. Fish fed diet B containing 31% protein and a lower energy level of 16 MJ kg^?1 with the same P/E ratio of 18.61 as diet F showed significantly lower weight gain and growth performance than diet F. Diets E and H containing 31% crude protein at all three energy levels produced similar results as diet B. The poorest FCR was observed when the diet contained both lower levels of protein and energy. Fish fed diet G, containing 26% protein at high energy level (22 MJ kg^?1), showed the best PER and NPR values. The PER and NPR were the poorest on diet C containing 36% protein at low energy level (16 MJ kg^?1). The body moisture content at all protein levels decreased (P < 0.05) with the increasing level of dietary energy whereas the body fat content increased (P < 0.05). Similar trends were observed in the body ash and energy content. Increasing the dietary energy content at lower protein levels did not show any difference (P > 0.05) in body protein content. Our results indicated the optimum P/E ratio for O. niloticus as 18.96 g protein per mega joule of gross energy at 36% dietary protein level and a dietary gross energy value of 19 MJ kg^?1.     

The influence of sulphur,molybdenum and cadmium exposure on the growth of goat,cattle and pig

A three factorial designed feeding experiment with common carp (Cyprinus carpio L.) was carried out in an intensive experimental rearing system. Fish (initial body weight 200 g) were fed on two different levels of dietary energy (16 and 18 MJ DE/kg DM), two different levels of protein (320 and 420 g CP/kg DM) and also two different feeding intensities (100% and 75% of the maximum intake). The experiment was terminated when fish reached a mean body weight of 1300 g.

Growth, feed utilization and nutrient composition of the whole body and fillet were observed. The highest growth was obtained when the fish were fed on the diet containing high dietary energy and high dietary protein with satiation feeding. High dietary energy, high dietary protein and restriction of feed intake improved feed conversion ratios. High dietary energy, low dietary protein and restrictive feeding increased energy utilization. Low dietary protein and restrictive feeding resulted in better protein utilization.

Fish fed with high dietary energy contained more fat and less protein in their carcasses. A lower fat content but higher protein and higher ash content in fish carcasses was shown when fish were fed with a diet high in protein and fed restrictively.     

Effect of increasing inclusion rates of tofu by-product in diets of growing pigs on nitrogen balance and ammonia emission from manure

To reduce competition with human-edible feed resources, it is of interest to incorporate by-products from the food industry in animal feeds. The current research investigated the effect of including increasing amounts of tofu by-product (TF) in practical pig diets on animal performance, nitrogen balance and ammonia emissions from manure. Two experiments were conducted including a control diet without TF, containing 160 g/kg dietary non-starch polysaccharides (NSPs) and three diets including 122, 246 and 360 g TF/kg DM (TF122, TF246 and TF360, respectively) to reach 220, 280 and 360 g/kg NSP. All diets had the same level of CP and protein digestible in the small intestine which particularly was realized by replacing rice bran with TF. Animal performance was assessed in a first experiment with 40 growing barrows with initial BW of 26.6 ± 1.80 kg (M ± SD) being allocated to the 4 treatments, during 2 growth phases (i.e. until 50 kg BW and from 50 to 80 kg BW). In the growth phase until 50 kg, feed intake and average daily gain (ADG) were linearly reduced by dietary TF inclusion, while this negative impact disappeared during the second growth phase (50 to 80 kg BW). Tofu by-product inclusion even positively affected the feed conversion ratio during this second growth phase (3.4 to 2.7 kg feed/kg ADG for 0 to 360 g/kg dietary TF). Over the entire growth period, performance and feed intake were negatively affected at the highest dietary TF level. Experiment 2 was conducted to assess digestibility, nitrogen balance and ammonia emission from manure. For this purpose, 16 pigs with BW of 62.8 ± 3.6 kg (M ± SD) were assigned to either 1 of the 4 treatments. There was no difference in total tract apparent digestibility of dietary organic matter or CP, while NDF digestibility increased with increasing TF level, suggesting increasing importance of the hindgut fermentation when digesting diets with increasing TF levels. Nevertheless, this was not reflected in increasing levels of faecal volatile fatty acids or purines, nor in reduced manure pH. As a result, ammonia emission from slurry was not reduced through dietary TF inclusion, despite the linear decrease in urinary nitrogen. In conclusion, TF can be included in pigs’ diets up to an inclusion rate of 25% without risk of impaired animal performance; however, this dietary strategy fails to mitigate ammonia emission from slurry.