Total Lysine Research Articles

Lysine-containing proteins in maize endosperm: a major contribution from cytoskeleton-associated carbohydrate-metabolizing enzymes.

We measured fresh weight, dry weight, total protein, and the amounts of several individual proteins during endosperm development in three varieties of maize ( Zea mays L.): W64A wild-type (WT) and opaque-2 (o2), and sweet corn (SW). By 28 days after pollination (DAP), fresh weight was much higher in WT and SW than in o2, but o2 had a higher dry weight and thus a much lower water content. By 28 DAP, protein concentration [mg (g tissue(-1))] was highest in o2 and lowest in WT, while the protein content (microg seed(-1)) was lowest in o2. The storage proteins, alpha- and gamma-zeins, were low initially, but by 28 DAP they comprised over 50% of the total protein in WT and SW, but only about 30% in o2. In all varieties, the cytoskeleton proteins, actin, tubulin and eEF1alpha, sedimented with the protein bodies at 30 g to 27,000 g in tissue homogenized in cytoskeleton-stabilizing buffer. Other cytoskeleton-associated proteins increased during development, including UDP-glucose starch glucosyltransferase (UDP-GSGT, EC 2.4.1.11), sucrose synthase 1 (SuSy-1, EC 2.4.1.13) and fructose-1,6 bisphosphate aldolase (FBA, EC 4.1.2.13). At 28 DAP, these cytoskeleton-associated proteins combined make up 27% (WT), 23% (SW) and 33% (o2) of the total protein. These proteins are all rather high (5-11%) in lysine, and so they contribute about 75% (WT), 67% (o2), and 51% (SW) of the total endosperm lysine. We conclude that efforts to elevate the levels of these proteins could make a significant contribution to the nutritional value of corn.

Sensitivity to dietary lysine: energy content in pigs divergently selected for components of efficient lean growth rate

AbstractThe sensitivity to dietary lysine: energy content of pigs from lines divergently selected over seven generations for components of efficient lean growth rate was quantified by the within-selection line regression of performance test traits on diet class. Large White pigs were performance tested over three 14-day test-periods starting at 30, 50 and 75 kg and offered, to appetite, isoenergetic diets differing in dietary total lysine: energy (0•59, 0•69, 0•81, 0•91, 1•01, 1•12 and 1•23 g/MJ digestible energy (DE)). Within each litter, full-sibs were performance tested on different diets. Pigs were also performance tested on a diet-choice procedure using diets with total lysine: energy of 0•69 and 1•12 g/MJ DE to determine the correlation between performance on phase-feeding and diet-choice.The study consisted of 578 animals with 459 pigs tested with phase-feeding and 119 tested on diet-choice procedures. The study detected significant selection line and dietary effects on performance test traits, but no significant between-selection line differences in sensitivity to dietary total lysine: energy. When combinations of performance test traits were transformed into predicted lysine and energy utilization traits there were significant selection line effects on predicted nutrient allocation, but not in responses to increasing dietary total lysine: energy. The lack of between-selection line differences in sensitivity to dietary total lysine: energy indicated that the consequences of changing dietary total lysine: energy will be broadly similar across a range of genotypes, as spanned by the selection lines of the study.Genetic correlations between performance traits of phase-fed and diet-choice pigs suggested that predictions of genetic merit will be similar with animals tested on either procedure between 30 and 75 kg but post 75 kg predicted genetic merit for growth rate and lysine intake should be estimated separately for performance on diet-choice or for performance on a given diet. In contrast, predicted genetic merit for fat deposition with performance testing on diet-choice will be highly correlated with predicted genetic merit with testing on a single diet.

Lisina em rações para suínos machos castrados selecionados para deposição de carne magra na carcaça dos 95 aos 110 kg

Foram utilizados 60 suínos machos castrados, provenientes de cruzamento entre híbridos comerciais, com peso inicial médio de 95,7 ± 0,8 kg e final de 109,8 ± 1,1 kg para avaliar diferentes níveis de lisina sobre o desempenho e as características de carcaça. Foi usado o delineamento de blocos ao acaso, com cinco tratamentos, seis repetições e dois animais por repetição. Os tratamentos corresponderam a uma ração basal com 13,7% de proteína bruta, 3367 kcal de ED/kg e suplementada com cinco níveis de L-lisina-HCl, resultando em rações com 0,50; 0,60; 0,70; 0,80 e 0,90% de lisina total. O consumo de ração diário reduziu de forma linear. Entretanto, ficou caracterizada maior ingestão de lisina com o aumento da concentração dietética do aminoácido. Verificou-se efeito quadrático do nível de lisina sobre a conversão alimentar, que melhorou até o nível de 0,76% de lisina, e sobre a conversão alimentar em músculo, que reduziu de forma linear. No entanto, os dados ajustados pelo modelo "Linear Response Plateau" indicaram o nível de 0,79% para a melhor conversão alimentar em músculo. O ganho de peso, comprimento de carcaça, espessura de toucinho, rendimento de pernil, rendimento de carne magra e a área de olho de lombo não foram influenciados pelos tratamentos. Para o genótipo estudado, o nível de 0,76% de lisina total na ração foi o indicado para machos castrados, dos 95 aos 110 kg, correspondendo à ingestão diária estimada de 23,8 g de lisina.

Níveis de lisina em ração de lactação para fêmeas suínas primíparas

Foram utilizadas 40 porcas mestiças (Landrace x Large White) de primeiro parto, com peso médio de 182,2 ±16,5 kg para avaliar diferentes níveis de lisina total (0,95; 1,03; 1,10; 1,18; e 1,25%) na ração, mantendo-se a mesma relação de aminoácidos, durante a lactação (21 dias). Utilizou-se o delineamento de blocos ao acaso com cinco tratamentos, oito repetições, sendo a porca considerada a unidade experimental. O consumo total de ração não variou entre os tratamentos, com as porcas consumindo, em média, 4,2 kg de ração por dia. O consumo de lisina e o peso das porcas à desmama aumentaram de forma linear, em razão do nível de lisina das rações. Embora a variação de peso das porcas não tenha sido significativa, as porcas que consumiram as rações com níveis de lisina iguais ou superiores a 1,18% apresentaram menores valores absolutos de perda de peso durante a lactação. O ganho de peso e o peso à desmama dos leitões e da leitegada, a espessura de toucinho e o número de dias para a retomada do estro das porcas após a desmama não foram influenciados pelos níveis de lisina da ração. Concluiu-se que o nível de 0,95%, correspondente a um consumo diário de 40 g de lisina total, atende às exigências de lisina de porcas primíparas em lactação.

EFFECT OF ALKALI TREATMENT ON THE NUTRITIONAL CHARACTERISTICS OF SOYBEAN (GLYCINE MAX) ALBUMINS AND GLOBULINS

The alkali treatment, commonly named nixtamalization, was evaluated on its effect on certain nutritional properties of soybeans. Albumin and globulin fractions were separated and evaluated in their total protein, % digestibility, lysine availability and total amino acid contents. Alkali treatment improved the % digestibility of whole soybean meal and that of the albumin fraction, with no apparent effect on the % digestibility of the globulin fraction. A significant increase was found for the lysine availability of the albumin fraction, caused by the alkali treatment. The total amino acid contents were higher in the alkali-treated whole soybean meal, but both extracted protein fractions, albumins and globulins, were consistently lower in their total amino acid contents. Alkali treatment may represent an alternative to increase soybean utilization for direct human consumption.

Exigências nutricionais de lisina para codornas durante a fase de postura, em função do nível de proteína da ração

O experimento objetivou estimar as exigências de lisina total e a relação lisina: proteína em codornas, na fase de produção. Foram utilizadas 320 codornas, resultado do cruzamento entre a codorna japonesa e a européia de 60 a 144 dias de idade, com peso vivo médio de 178+12 g, alimentadas com rações contendo 20 e 23% de proteína bruta (PB) e, 0,80; 0,95; 1,10; 1,25 e 1,40% de lisina. O delineamento experimental foi o inteiramente ao acaso em esquema fatorial 2x5 (dois níveis de PB x cinco níveis de lisina), que resultou em dez tratamentos, cada um com quatro repetições de oito aves. As codornas foram submetidas a um programa de luz de 17 horas de duração e alimentadas à vontade. As variáveis estudadas foram obtidas em quatro períodos de 21 dias. Houve efeito quadrático dos níveis de lisina sobre a produção de ovos, sendo a exigência e o consumo, respectivamente, de 1,07% e 287 mg de lisina/dia com 20%PB e de 1,15% e 321 mg de lisina/dia com 23%PB. O nível de 23%PB aumentou o consumo de ração, produção, peso e massa de ovos e também melhorou a conversão alimentar por massa e dúzia de ovos. As relações lisina: PB não foram alteradas, sendo de 5,3 e 5,0%, respectivamente, com 20 e 23% de PB na ração. Os resultados do presente estudo sugerem aumento quantitativo da exigência de lisina de codornas na fase de produção, mas não da relação lisina: PB, à medida que a concentração de PB na ração é elevada.

Serum urea concentration as a predictor of dietary lysine requirement in selected lines of pigs.

Serum urea concentrations were measured in Large White pigs from lines divergently selected for components of efficient lean growth rate and performance tested over three 14-d test periods starting at 30, 50, and 75 kg. Two methods of performance testing were used. Phase-fed pigs were fed to appetite isoenergetic diets differing in total lysine:energy ratio (0.58, 0.69, 0.81, 0.91, 1.01, 1.12, and 1.23 g/MJ of digestible energy), whereas diet-choice pigs were offered a choice of the 0.69 and 1.12 lysine:energy diets. Between test periods, all animals were fed one diet: 0.91 g of lysine/MJ of digestible energy. The study consisted of 230 boars and gilts with 150 pigs performance tested on phase-feeding and 80 pigs on diet-choice. The line selected for high lean food conversion had lower urea concentrations on each diet than the line selected for high lean growth rate, despite similar predicted lysine balances. Efficiency of lean growth rather than the rate of lean growth may be a better selection strategy in the context of nitrogen excretion. Urea concentrations at the end of each test period were correlated with lysine intake (0.33, 0.48 and 0.65; standard error, 0.08) and predicted lysine balance (0.39,0.44, and 0.64), but were uncorrelated with predicted lysine for protein deposition (0.01, 0.08, and 0.08) and maintenance. Urea concentration at the end of a test period was not a useful predictor of protein deposition, even after accounting for pretest variation in urea concentration and food intake during test. The expected response pattern of serum urea concentration to diets differing in total lysine:energy would be nonlinear, with the point of inflection occurring at the required dietary total lysine:energy for each genotype. However, there was no evidence of such an inflection point such that the prediction of lysine requirement from urea concentration was not possible for the selection lines in the study.

Effects of increasing dietary lysine in phase ii diets (15- to 25-lb) on nursery pig growth performance (2003)

A total of 1,260 weanling pigs (initially 18.6 lb) was used in a 19 d growth assay (d 10 to 29 after weaning) to determine the effects of increasing lysine in Phase II diets on nursery pig growth performance. All pigs were weaned and fed 1.2 lb per pig of a SEW diet, then switched to a transition diet until day 10 after weaning. Pigs were then weighed and switched to experimental diets containing true digestible lysine levels of 1.22, 1.32, 1.42, 1.52, and 1.62%, corresponding to approximately 1.36, 1.47, 1.56, 1.65, and 1.75% total lysine. All diets were formulated to contain 30% soybean meal, with increasing amounts of synthetic amino acids to achieve desired amino acid concentrations in the diets. From d 10 to 17 after weaning, increasing lysine increased ADG (quadratic, P<0.04) and improved feed efficiency (quadratic, P<0.01), with both appearing to be maximized at 1.52% true ileal digestible lysine. From d 17 to 24 and 24 to 29, ADFI and F/G improved (linear, P<0.05) with increasing true ileal digestible lysine. For the overall study, (d 10 to 29 after weaning), increasing true ileal digestible lysine increased ADG (quadratic, P<0.07) and improved feed efficiency (quadratic, P<0.001). In conclusion, 1.52% true ileal digestible lysine maximized both ADG and F/G early in the study, but the lysine requirement appeared to decrease to 1.42% from d 17 to 24. Results of two recent studies conducted at the University of Missouri with similar lysine levels fed to 15- to 25-lb pigs suggest a requirement estimate between 1.32 and 1.42% true ileal digestible lysine, slightly lower than the requirements observed in the present study.; Swine Day, 2003, Kansas State University, Manhattan, KS, 2003

The optimal true ileal digestible lysine requirement for 22 to 45 lb pigs (2003)

A total of 1,440 pigs (initially 22.5 lb and 21 d after weaning) was used in a 21-d growth assay to determine the optimal lysine level to maximize growth performance of 22- to 45-lb pigs. Pigs were fed one of five dietary treatments with increasing dietary lysine (1.1, 1.2, 1.3, 1.4 and 1.5% true digestible lysine). All diets had the same soybean meal level with crystalline amino acids added to achieve the increasing lysine levels while maintaining a minimum ratio of all other amino acids to lysine. Average daily gain and feed efficiency improved linearly (P<0.01) with increasing dietary lysine. Although the response to lysine was linear (P<0.01), it would appear that pigs weighing between 22 and 45 lb require approximately 1.4% true digestible lysine (1.54% total lysine) to maximize growth performance.; Swine Day, 2003, Kansas State University, Manhattan, KS, 2003

Coexpression of the soybean vegetative storage protein beta subunit (S-VSPbeta) either with the bacterial feedback-insensitive dihydrodipicolinate synthase or with S-VSPalpha stabilizes the S-VSPbeta transgene protein and enhances lysine production in transgenic tobacco plants.

Soybean vegetative storage proteins (S-VSPs) are lysine-rich leaf proteins, originally found to accumulate to high levels in depodded soybean plants. In the present study, we overexpressed S-VSPbeta, the ruminant stable subunit of the S-VSP genes, in transgenic tobacco plants. The S-VSPbeta protein accumulated in all organs studied, but its level declined drastically with leaf age. This instability of S-VSPbeta could be overcome either by elevating free lysine levels or by coexpressing S-VSPbeta with S-VSPbeta. High levels of rumen-stable, lysine-rich proteins is expected to improve absorption of lysine by ruminants. Furthermore, the expression of S-VSPs in heterologous plants led to a significant increase in total soluble lysine, suggesting that these proteins may also permit better assimilation of lysine by humans and monogastric animals.

Effects of increasing dietary lysine in transition diets on nursery pig growth performance (2003)

A total of 1,400 weanling pigs (initially 13.6 lb) was used in a 9 d growth assay (d 4 to 13 postweaning) to determine the effects of increasing lysine in the transition diet on nursery pig growth performance. All pigs were fed a common SEW diet until d 4 after weaning. Pigs were then switched to experimental diets with total dietary lysine levels of 1.40, 1.50, 1.60, 1.70 or 1.80%. All diets were formulated to contain 20% soybean meal, with increasing amounts of synthetic amino acids to achieve desired amino acid concentrations in the diets. From d 4 to 9 postweaning, increasing lysine increased ADG (linear, P<0.03) and improved feed efficiency (linear, P<0.001), but ADFI was not affected. Overall (d 4 to 13 postweaning), pigs fed diets containing increasing dietary lysine had improved ADG (linear, P<0.03) and feed efficiency (linear, P<0.001), with no differences in ADFI. Although responses to increasing dietary lysine were linear, there was little improvement either ADG or F/G above 1.7% lysine. There was no difference in average pig weight at the end of the trial, probably because of the short duration of the study. In conclusion, increasing dietary lysine up to 1.7% in transition diets (13 to 19 lb) for nursery pigs maximized growth performance.; Swine Day, 2003, Kansas State University, Manhattan, KS, 2003

Lysine need of heavy broiler males applying the ideal protein concept

An experiment was conducted to measure the response of broiler males to dietary lysine progressing from 0.75 to 1.15% between 42 and 56 d of age. Chicks (Ross × Ross 308) were placed in floor pens (30 pens having 35 chicks each) of an open-sided house and provided common feeds to 42 d of age. From 42 to 56 d, a corn-soybean meal diet (18% CP and 3,250 kcal/kg ME) having total lysine at 0.75% was supplemented with additions of 0.10% until 1.15%. All other essential amino adds were “ideally” balanced to one another within the limits of practicality assuming 0.85% total lysine. Birds had continuous access to feed, water, and light. Live performance during experimentation was particularly favorable. Weight gain between 42 and 56 d of age was similar among birds receiving all levels of lysine, while feed conversion was optimized at 0.85%. Depot fat removed from the abdominal cavity, yield of the resultant chilled carcass, and the amount of fillet (pectoralis major) cone deboned from the breast were unaltered by dietary lysine level. However, yield of tenders (pectoralis minor) decreased as supplemental lysine increased, whereas the incidence of myopathy (green muscle disease) increased. The lysine requirement of 0.85% as advocated by NRC (1994) for broilers between 42 and 56 d of age is in agreement with present results and may have been predisposed by its favorability of balance with all other essential amino adds.

Formulação das dietas, desempenho e qualidade da carcaça, produção e composição de dejetos de suínos

A eficiência de utilização dos alimentos pelos animais pode ser influenciada pela maneira como as informações de composição e digestibilidade dos nutrientes são utilizadas. A formulação de rações para suínos baseada no conceito de proteína bruta pode apresentar níveis de aminoácidos desbalanceados ocasionando a desaminação dos aminoácidos em excesso. O nitrogênio disponível pode ser utilizado na síntese de outros compostos ou simplesmente excretado, o que significa perda de eficiência no processo e aumento da capacidade poluente dos dejetos produzidos. Assim, foram realizados dois experimentos para estudar os efeitos do uso de formulação de dietas para suínos em crescimento e terminação. As dietas foram: 1) formulação baseada nas exigências de proteína bruta e aminoácidos totais do NRC; 2) formulação com níveis de lisina (Lys) total 15% superiores ao da dieta 1; 3) formulação com teor de proteína semelhante ao da dieta 2 mas atendendo a proteína ideal; 4) formulação atendendo a proteína ideal proposta por Baker (1997), com 15% mais Lys digestível mantendo-se o mesmo teor de proteína. Os animais que receberam as dietas 2 e 4 apresentaram maior ganho de peso diário. Para espessura de toucinho, profundidade de lombo e porcentagem de carne não houve efeito de tratamento. As dietas com níveis de proteína mais elevados proporcionaram maior excreção de fezes. Os animais que receberam as dietas formuladas com 15% mais Lys (dietas 2 e 4) apresentaram menor excreção de nitrogênio nas fezes, sem afetar a excreção deste na urina.

Feed intake, growth and carcass parameters of swine consuming diets containing low levels of deoxynivalenol from naturally contaminated barley

The ubiquitous nature of deoxynivalenol (DON) in the eastern prairie region of Canada necessitates the development of strategies to enhance the utilization of affected grains by swine producers. To this end, an experiment was designed to determined the impact of low levels of DON on feed intake and growth of swine. 144 Cotswold pigs (initial weight = 23.4 kg ± 0.3 SE) were assigned to receive diets containing either 0, 1 or 2 ppm DON in the final feed (four pens, each containing six barrows and six gilts, per treatment). The final DON contents of the diets were derived by diluting DON-contaminated barley (DON = 4.9 ppm) with DON-free barley. Diets were formulated to provide a minimum of 13.4 MJ kg-1 digestible energy (DE) and 0.81% total lysine, and the same diets were used throughout the grow-finish period. Feed intake (per pen basis; kg d-1), body weight gains (kg d-1) and feed conversion were measured on a weekly basis. Pigs were slaughtered at approximately 110 kg and indices of carcass merit collected. The presence of 2 ppm DON depressed feed intake by 7.6% (P &lt; 0.05) relative to 0 ppm DON controls, with pigs consuming the 1 ppm DON diet having intermediate levels of feed depression. However there was no significant effect of DON on average daily gain or feed conversion at any stage of the experiment, The presence of DON in the diet increased the proportion of animals reaching 110 kg, estimated from individual regression curves, at times greater than the median value (169.5 d; chi-squared analysis P &lt; 0.05), in gilts, but was without effect on barrows (median = 158.2 d). Measures of carcass weight, index, backfat thickness, and depth of lean over the loin were not affected (P &gt; 0.05) by the presence of DON in the diet, irrespective of gender, however there was significant linear effect of DON (P &lt; 0.05) on the loin premiums received, with higher values realized with increasing DON content in the diet. The current data provide evidence that grains containing DON could be used in the diets of barrows to provide 2 ppm in the final feed however, caution is required when considering their utilization for gilts. Key words: Deoxynivalenol, feed intake, performance, swine, barley, carcass merit

Effects of increasing dietary niacin on growth performance and meat quality in finishing pigs reared in two different environments.

We conducted two experiments to determine the effects of added dietary niacin on growth performance and meat quality in finishing pigs. Pigs were blocked by weight and assigned to one of six dietary treatments in both experiments. Dietary treatments consisted of a corn-soybean meal-based control diet (no added niacin) or the control diet with 13, 28, 55, 110, or 550 mg/kg of added niacin. In Exp. 1, pigs were housed at the Kansas State University research from with two pigs per pen (six pens per treatment per sex). In Exp. 2, pigs were housed with 26 pigs per pen (four pens per treatment per sex) in a commercial research barn. In Exp. 1, 144 pigs (initially 51.2 kg) were fed diets in two phases (d 0 to 25 and 25 to 62) that were formulated to 1.00 and 0.75% lysine, respectively. In Exp. 2, 1,248 pigs (initially 35.9 kg) were fed diets in four phases (d 0 to 28, 29 to 56, 57 to 84, and 85 to 117), with corresponding total lysine concentrations of 1.25, 1.10, 0.90, and 0.65% lysine, respectively. Added fat (6.0%) was included in the first three phases. In Exp. 1, average daily feed intake tended (quadratic, P < 0.07) to increase then return to values similar to control pigs as dietary niacin increased. Longissimus muscle (LM) 24-h pH (longissimus of pigs fed added niacin) tended to increase (control vs niacin, P < 0.06) for pigs fed added niacin. In the commercial facility (Exp. 2), increasing added niacin improved gain:feed (quadratic, P < 0.01) and subjective color score, and ultimate pH (linear, P < 0.01). Added niacin also decreased (linear, P < 0.04) carcass shrink, L* values, and drip loss percentage. Results from these two studies show that 13 to 55 mg/kg added dietary niacin can be fed to pigs in a commercial environment to improve gain:feed. It also appears that pork quality, as measured by drip loss, pH, and color, may be improved by higher concentrations of added dietary niacin.

Effect of supplementation on physicochemical, sensory and nutritional characteristics of bread.

Supplementation of wheat flour with soy flour (full fat and defatted) at 5, 10, 15 and 20% levels was carried out to test the effect on physico-chemical, sensory, nutritional evaluation and shelf life of breads. Adding 10% of soy flour (full fat and defatted) produced breads with good baking and organoleptic characteristics. However, at 15 and 20% levels they were less acceptable. The better breads were further investigated for various nutritional parameters and shelf life. Full fat and defatted soy flour (10%) supplemented bread exhibited 13.66 and 13.81% protein, and 3.02 and 3.05 g/100 g protein total lysine contents as compared to control (wheat) bread (11.47% protein and 2.36 g/100 g protein total lysine). Other nutrients are also increased in supplemented breads as compared to wheat bread. However, for storage, defatted soy supplemented bread exhibited better shelf life than the full fat version.

Combined expression of S-VSPalpha in two different organelles enhances its accumulation and total lysine production in leaves of transgenic tobacco plants.

Soybean vegetative storage proteins (S-VSPs) accumulate to high levels in vacuoles of both wild types and heterologous plants. Here it is shown that directing S-VSPalpha to two different organelles-chloroplasts and vacuoles-in a single transgenic plant significantly increased its accumulation. Accumulation of S-VSPalpha in heterologous plants correlated with total soluble lysine. Using this approach with essential amino-acid-rich transgene proteins may lead to a breakthrough in improving plant nutritional quality.

Exigência de lisina para frangos de corte machos no período de 22 a 42 dias de idade, mantidos em ambiente quente (26ºC)

Utilizaram-se 240 frangos de corte machos, Avian Farms, com peso médio de 541 &lt;FONT FACE=Symbol&gt;±&lt;/FONT&gt; 3,61 g, no período de 22 a 42 dias de idade, mantidos em ambiente de temperatura alta, para se determinar a exigência de lisina. O delineamento experimental utilizado foi o inteiramente casualizado, com cinco tratamentos (0,88; 0,94; 1,00; 1,06; e 1,12% de lisina total), seis repetições e oito aves por repetição. Durante o período experimental, a temperatura manteve-se em 25,6 &lt;FONT FACE=Symbol&gt;±&lt;/FONT&gt;0,24ºC; a umidade relativa, em 68,4 &lt;FONT FACE=Symbol&gt;±&lt;/FONT&gt; 6,30%; a temperatura de globo negro, em 25,7 &lt;FONT FACE=Symbol&gt;±&lt;/FONT&gt; 0,25ºC; e o Índice de Temperatura de Globo e Umidade (ITGU), em 74 &lt;FONT FACE=Symbol&gt;±&lt;/FONT&gt; 0,6. O fornecimento de ração e água foi à vontade. Os níveis de lisina da ração influenciaram o ganho de peso e a conversão alimentar, que aumentaram e melhoraram até os níveis de 1,05 e 1,03%, respectivamente. O consumo de ração não foi influenciado pelos níveis de lisina da ração. Quanto à composição da carcaça, observou-se que os tratamentos influenciaram de forma quadrática a taxa de deposição de proteína, que aumentou até o nível de 1,05% de lisina. Os tratamentos influenciaram o peso absoluto da carcaça, peito com osso, perna, sobrecoxa e gordura abdominal e o peso relativo do peito com osso e da gordura abdominal. Concluiu-se que frangos de corte, no período de 22 a 42 dias de idade, submetidos à temperatura ambiente de 25,6ômicronC, exigem 1,05% de lisina total para máximo desempenho e deposição de proteína na carcaça.

Serum neuropeptide Y (NPY) and leptin concentrations in pigs selected for components of efficient lean growth

Responses in log transformed serum neuropeptide Y (NPY) concentration and leptin concentration after six generations of divergent selection on components of efficient lean growth in pigs were measured. From an animal breeding perspective, serum NPY and/or leptin concentrations could be used as physiological predictors of genetic merit if there were significant responses to selection. At 90 kg liveweight, log transformed serum NPY concentrations were increased with divergent selection for low food conversion ratio (LFC) (6.31 versus 5.72, SED 0.09 log(pmol/L)) or for high lean growth rate (LGA) (5.80 versus 5.37 log(pmol/L)) but not with selection on daily food intake (DFI) (6.26 versus 6.14 log(pmol/L)). Selection for high DFI was associated with increased serum leptin concentration (3.06 versus 2.45, SED 0.21 ng/mL human equivalent (HE)) as was selection for low LFC (3.04 versus 2.46 ng/mL HE). Correlations between leptin and predicted lipid weight increased with stage of test (0.13, 0.34 and 0.43, SE 0.08 at 30, 50 and 75 kg). The high correlations between successive serum NPY concentrations (0.80, SE 0.11) suggest that changes in body composition with time would not be reflected in serum NPY concentrations. Serum NPY and, to a lesser extent, serum leptin concentrations were insensitive to dietary differences in total lysine: energy and indicated that studies using a genetic resource population of animals may be more powerful than nutritional studies using isoenergetic diets differing in lysine content to examine aspects of function of serum concentrations of NPY and leptin in pigs.

Apparent ileal digestibility of amino acids in protein feedstuffs and diet formulation based on total vs digestible lysine for poultry

A digestibility experiment was carried out with 140 Ross-broiler chickens (age 24 days) to determine coefficient of ileal apparent digestibility (CIAD) of amino acids in meat and bone meal (MBM), full-fat soyabeans (FFSs), soyabean cake and meal, full-fat rapeseeds, and rapeseed cake and meal. The birds were fed semi-purified diets which contained protein feedstuffs as a sole protein source and chromium mordanted straw as an indigestible marker. The CIAD of nutrients were assessed using the slaughter technique. A 37-day growth experiment was carried out with 2880 Ross-broiler chickens to compare feed formulation systems based on apparent ileal digestible or total lysine content. Three barley based diets were formulated to be similar in total lysine content (9.5 g/kg feed). Diet 1 contained soyabean meal (SBM) (280 g/kg DM), Diet 2 SBM (180 g/kg DM) and rapeseed meal (RSM) (171 g/kg DM) and Diet 3 a combination of SBM (78 g/kg DM), RSM (172 g/kg DM) and MBM (87 g/kg DM). The composition of Diets 4 and 5 was similar to that of diets 3 and 4, respectively, except that they were supplemented with l-lysine–HCl to obtain a similar apparent ileal digestible lysine content as in Diet 1 (7.9 g/kg feed). The total lysine content of Diets 4 and 5 was 10 g/kg feed. Furthermore, Diet 1 was supplemented with l-lysine–HCl to obtain Diet 6, in which the total and apparent ileal lysine contents were 10 and 8.5 g/kg feed, respectively. CIAD of lysine, methionine, threonine and cystine were respectively 0.60, 0.66, 0.48 and 0.34 for MBM; respectively 0.81, 0.75, 0.68 and 0.67 for FFSs; respectively 0.86, 0.86, 0.76 and 0.62 for soyabean cake; respectively 0.85, 0.84, 0.74 and 0.63 for SBM; respectively 0.59, 0.59, 0.43 and 0.53 for full-fat rapeseeds; respectively 0.68, 0.81, 0.64 and 0.53 for rapeseed cake; and respectively 0.63, 0.75, 0.54 and 0.43 for RSM. Final weight and growth rate were highest when digestible lysine based feed formulation was used compared to that based on total lysine ( P<0.001). The increase in final weight was largest for diet containing MBM and formulated based on digestible lysine ( P<0.001). In addition, the proportion of breast muscle of total live-weight and weight of breast muscle increased ( P<0.05) in animals fed diets formulated on the basis of digestible compared to total lysine. However, diet formulation based on digestible lysine impaired feed conversion ratio compared to that of total lysine for birds fed SBM as the sole source of supplementary protein compared to diets containing rapeseed or MBM ( P<0.01). Growth rate and final weight were higher in birds fed diets containing SBM alone compared to those also containing RSM and MBM ( P<0.001). In addition, the effect of diet formulation based on digestible lysine on performance results of broilers was more obvious in males than females ( P<0.05). The results indicated that formulation of diets based on a digestible lysine was better than that based on total lysine when diets contained protein sources of low amino acid digestibility such as meat and bone and RSMs.