Biomedical subjects

C M Parsons

Publications and source records attributed to C M Parsons.

At least 37 records · Page 2Linked to original sources

PubMed2003

Nutritional evaluation of dried tomato seeds.

Two samples of tomato seeds, a by-product of the tomato canning industry were evaluated to determine proximate analysis, amino acid content, and digestibility, TMEn, and protein efficiency ratio. Tomato seeds were also used to replace corn and soybean meal (SBM) in a chick diet on an equal true amino acid digestibility and TMEn basis. Tomato seeds were found to contain 8.5% moisture, 25% CP, 20.0% fat, 3.1% ash, 35.1% total dietary fiber, 0.12% Ca, 0.58% P, and 3,204 kcal/kg of TMEn. The total amounts of methionine, cystine, and lysine in the tomato seeds were 0.39, 0.40, and 1.34%, respectively, and their true digestibility coefficients, determined in cecectomized roosters, were 75, 70, and 54%, respectively. The protein efficiency ratio (weight gain per unit of protein intake) value when fed to chicks at 9% CP was 2.5 compared to 3.6 for SBM (P < or = 0.05). When corn-SBM diets were formulated on an equal true amino acid digestibility and TMEn basis, up to 15% tomato seeds could replace corn and SBM without any adverse affects on chick weight gain, feed intake, or gain:feed ratio from 8 to 21 d posthatch. Tomato seeds at any level in the diet did not significantly affect skin pigmentation. Although the protein quality of tomato seeds may not be as high as SBM, tomato seeds do contain substantial amounts of digestible amino acids and TMEn. When formulating diets on a true digestible amino acid and TMEn basis, tomato seeds can be supplemented into chick rations at up to 15% without any adverse affects on growth performance.

Animal Feed↗

PubMed2003

Impact of galactose, lactose, and Grobiotic-B70 on growth performance and energy utilization when fed to broiler chicks.

Three chick assays were conducted to determine the effect of increasing dietary galactose (GAL), lactose (LAC), and Grobiotic-B70, a LAC fermentation product, on growth performance, toxicity, and energy utilization when fed to commercial broiler chicks. One-day-old male commercial broiler chicks were randomly assigned to treatments in each assay. In all assays, a 22% CP corn-soybean meal-dextrose basal diet containing a growth-promoting antibiotic (Bacitracin methylene disalicylate) was fed. In assay 1, GAL was added at 2, 4, 6, 10, or 15%. In assay 2, Grobiotic-B70 was added at 5%. In assay 3, GAL, LAC, and Grobiotic-B70 were each added at 2, 4, and 6%. All additions were made in place of dextrose, and diets were fed from 0 to 20 or 21 d of age. In assay 1, the 15% GAL treatment resulted in high mortality (27%) by d 3 and was terminated. The 10% GAL treatment also resulted in increased mortality, most of which occurred during the 7-to-14-d period. Inclusion of 2 and 4% GAL resulted in an improvement (P < 0.05) in growth compared to the basal diet. Inclusion of 2, 4, 6, and 10% GAL resulted in a significant linear decrease in MEn (r2 = 0.85). In chick assay 2, 5% Grobiotic-B70 increased growth during the first 2 wk. In chick assay 3, 6% Grobiotic increased weight gain (P < 0.05) from 0 to 14 d, and addition of 2 or 4% GAL, 2 or 4% LAC, and 4 or 6% Grobiotic-B70 increased weight gain (P < 0.08) from 0 to 21 d. Our results indicate that levels of 10 to 15% GAL are toxic. In contrast, low levels of GAL and Grobiotic-B70, and possibly LAC, may increase growth of commercial broiler chicks.

Animal Feed↗

PubMed2003

Interrelationship between environmental temperature and dietary nonphytate phosphorus in chicks.

Four levels of nonphytate P (NPP; 0.2, 0.3, 0.4, and 0.5%; total P = 0.46, 0.56, 0.66, and 0.76%) and two temperatures (25 and 37 degrees C) were evaluated in chicks from 8 to 22 d. In experiment 1, crossbred male chicks (New Hampshire x Columbian) housed at 25 degrees C increased weight gain at all increasing NPP levels, but chicks exposed to 37 degrees C did not show increased weight gain beyond 0.3% NPP. In experiment 2, environmental temperature was not increased until d 15. Weight gain of crossbred male chicks fed the 0.2% NPP diet was similar at both temperatures, but chicks exposed to 37 degrees C had lower weight gains than chicks housed at 25 degrees C for all other NPP levels. On d 22 to 24, chicks that had been housed at 25 degrees C and fed 0.2, 0.3, and 0.5% NPP were moved to the 37 degrees C chamber to evaluate heat stress on older chicks. Chicks fed the 0.2% NPP diet showed 35% mortality within 6 h. In experiment 3, both male commercial (Ross x Ross) and crossbred chicks that had been housed at 25 degrees C and fed 0.2% NPP from 8 to 22 d showed increased signs of severe heat distress when exposed to 37 degrees C on d 22. Our results suggest that the NPP requirement for growth of 8-to-22-d-old chicks may be reduced by high temperature. However, a NPP deficiency may result in increased mortality or severe heat distress in older chicks that are exposed to an acute increase in temperature.

Aging↗

PubMed2003

Interrelationship between environmental temperature and dietary nonphytate phosphorus in laying hens.

Four experiments were conducted to evaluate the effects of phosphorus nutrition on laying hens exposed to heat stress (HS). Hens were fed their respective diet for at least 3 wk prior to initiation of each experiment to allow the hens fed low-P diets to become P deficient. In most experiments, hens housed in non-HS conditions were pair-fed to the HS hens to maintain equal feed intake. In experiments 1 and 2, two levels of nonphytate P (NPP; deficient at 0.10 or 0.16% vs. control at 0.45%) and two temperatures (constant thermoneutral at 21 degrees C or cyclic HS up to 35 degrees C) were evaluated. Low NPP significantly reduced feed intake and hen-day egg production, but the cyclic heat treatment had no effect on hen performance. Experiment 3 was similar to experiments 1 and 2 except that constant HS was implemented. Both constant HS and low dietary NPP reduced feed intake and egg production, and there was no significant interaction between HS and dietary NPP level. In experiment 4, hens were fed 0.10 or 0.45% NPP diets and exposed to a more severe HS (38 degrees C) for 8 h. Hens fed the deficient NPP level showed a 16% incidence of severe heat distress (unable to stand, unresponsive). Our results generally indicated that there was no interaction between dietary NPP level and HS in laying hens. However, subjecting hens that had been fed a P-deficient diet to an acute HS of 38 degrees C did increase the incidence of severe heat distress.

Animal Nutritional Physiological Phenomena↗

PubMed2003

1alpha-hydroxycholecalciferol has little effect on phytate phosphorus utilization in laying hen diets.

Previous research in our laboratory demonstrated marked increases in phytate P utilization when P-deficient corn-soybean meal diets were supplemented with 1a-hydroxycholecalciferol [1alpha-(OH) D3] and fed to chicks. Our objective was to determine if 1alpha-(OH) D3 would improve phytate P utilization when supplemented to vitamin D-adequate laying hen diets. The five experimental treatments were 1) P-deficient corn-soybean basal diet [17% CP, 3.8% Ca, and 0.10% nonphytate NPP)], 2) basal with 2.5 microg/kg 1alpha-(OH) D3, 3) basal with 5 microg/kg 1alpha-(OH) D3, 4) basal with 10 microg/kg 1alpha-(OH) D3, and 5) basal with 0.35% supplemental inorganic P (0.45% NPP, positive control). Diets were fed to six replicate groups of 12 HyLine W-98 White Leghorn laying hens from 44 to 52 wk of age. Hen-day egg production was significantly depressed by 47 wk of age for the basal diet treatment and by 47, 49, and 48 wk of age, respectively, for the 2.5, 5, and 10 microg/kg of 1alpha-(OH) D3 treatments compared to the positive control diet. Supplementation with 5 or 10 microg/kg 1alpha-(OH) D3 did improve (P < 0.05) egg production, but egg production for those treatments was much lower than that for the 0.45% NPP treatment. Our results indicate that 1alpha-(OH) D3 did not substantially improve P utilization in laying hens fed corn-soybean meal diets.

Animal Nutritional Physiological Phenomena↗

PubMed2003

Utilization of different soy products as affected by age in chicks.

Two experiments were conducted to evaluate the utilization of several different soy products at different ages in New Hampshire x Columbian male chicks. Six pens of eight chicks were fed dextrose-protein source diets (23% CP) containing 1 of 10 different protein sources from 0 to 21 d of age. Excreta were collected at 0 to 2, 3 to 4, 7, 14, and 21 d of age, and AMEn and amino acid (AA) digestibility were determined using acid-insoluble ash as a marker. Protein sources evaluated were as follows: Experiment 1--casein, soybean meal (SBM), soy protein concentrate (SPC), and soy protein isolate (SPI); Experiment 2-raw soyflakes, SBM, Williams 82 soybeans, heated Williams 82 soybeans, Kunitz-free soybeans (reduced trypsin inhibitor), lectin-free soybeans, and Kunitz/lectin-free soybeans. In Experiment 1, when comparing the MEn and AA digestibility values among diets at the same age, the ranking (from highest to lowest) for the four diets was casein, SPI, SPC, SBM. The MEn values increased (P < 0.05) with age for all four diets, with the increase being much smaller for the casein diet (3%) than the soy diets (mean increase of 13%). In Experiment 2, the SBM diet yielded the highest (P < 0.05) growth performance, MEn and AA digestibility values. The MEn and AA digestibility values of the Williams 82 soybeans, Kunitz-free soybeans, and lectin-free soybeans diets were much lower than those for the SBM diet. In general, the Kunitz/lectin-free soybeans yielded higher growth performance and MEn values than the Williams 82 soybeans, Kunitz-free soybeans, and lectin-free soybeans. The MEn values increased with age for most diets, and AA digestibility increased with age for the soyflake and Kunitz/ lectin-free soybean diets. Our results suggest there may be some potential benefits of feeding SPC or SPI during the first 1 to 3 wk posthatching and that underprocessed (under heated) soybeans should not be included in the diets of very young chicks.

Aging↗

PubMed2003

Phytase effects on amino acid digestibility in molted laying hens.

Two hundred sixteen previously molted Dekalb Delta Leghorn laying hens (78 wk of age) were utilized to determine the effect of phytase on the ileal digestibility of amino acids. The hens were randomly arranged in a 3 x 2 factorial to evaluate three diet types that were corn-soybean meal (C-SBM), C-SBM-meat and bone meal (C-SBM-MBM), and C-SBM-wheat middlings (C-SBM-WM) and two levels of phytase (0 or 300 U/kg of diet). Each treatment was administered to four replicates of nine hens per replicate. Hens were fed the experimental diets for 21 d, and daily egg production and feed intake were recorded. After 21 d, the hens were euthanized, and ileal contents were collected for amino acid and digestible energy determination. Egg production of the hens did not differ among the treatments (P > 0.05). A significant interaction between diet type and phytase level for Ala, Gly, Leu, and Met was observed. The interaction resulted because phytase numerically increased amino acid digestibilities for the C-SBM-MBM and C-SBM-WM diets, but phytase addition numerically decreased the amino acid digestibilities for the C-SBM diet. Diet type had a significant effect on digesibilites of most amino acids. The latter effect was due primarily to lower amino acid digestibilities for the C-SBM-MBM diet than the C-SBM-WM diet. Phytase had no significant affect on digestibility of any amino acid. Ieal digestible energy was significantly affected by diet type but not by phytase. In conclusion, diet type had a significant effect on apparent ileal amino acid digestibility and digestible energy, but phytase had no consistent effect.

6-Phytase↗

PubMed2003

Evaluation of nonfeed removal methods for molting programs.

An experiment was conducted using 336 White Leghorn hens (60 wk of age) randomly assigned to one of four treatments that consisted of feed removal for 4 or 10 d or no feed removal with ad libitum access to 95% corn or 95% wheat middlings molt diets that contained supplemental minerals and vitamins. At the end of the 4- or 10-d feed removal period, hens on these treatments were provided with the corn molt diet for 24 or 18 d, respectively. Hens on the corn or wheat middlings treatments were fed the diets for 28 d. At d 28, hens on all treatments were fed a corn-soybean meal (16% CP) layer diet for 40 wk (64 to 104 wk of age). Both feed removal and the wheat middlings treatments resulted in total cessation of egg production within 8 d. Egg production of hens fed the corn molt diet had decreased to 3% by d 28. Body weight loss for hens fed the corn or wheat middlings diet was approximately 15 and 8% at d 28, respectively. Hens fed the wheat middlings diet returned to production slightly faster than hens on the other treatments. Postmolt egg production and egg mass (wk 5 to 44) were generally higher for the wheat middlings and 10-d feed removal treatments than for the corn or 4-d feed removal treatments. There were no consistent differences in mortality, egg weight, egg specific gravity, feed efficiency, and layer feed consumption among treatments. This research indicates that diets with high corn or wheat middlings, particularly wheat middlings, are effective nonfeed removal methods for molting hens.

Animal Feed↗

PubMed2003

Efficacy of high available phosphorus corn in laying hen diets.

Our objective was to determine if high available phosphorus corn would provide sufficient available phosphorus (AP) to laying hens fed corn-soybean meal diets from 57 to 69 wk of age. Six replications of 12 Dekalb Sigma Leghorn hens were fed a normal yellow dent (YD) corn-soybean meal diet or high available phosphorus (HAP) corn-soybean meal diet without and with 0.04% supplemental inorganic P. The unsupplemented YD diet was calculated to contain 17% CP, 3.8% Ca, and 0.10% AP, and the unsupplemented HAP diet contained 17% CP, 3.8% Ca, and 0.16% AP. In addition, a positive control, YD diet (17% CP, 3.8% Ca, 0.45% AP) was also fed. The HAP corn was directly substituted for YD on a weight basis, and the amount of soybean meal was kept constant in all diets. Egg production, hen body weight, egg weight, egg mass, feed consumption, and feed efficiency were measured. The YD and the YD + 0.04% P treatments were terminated at 61 and 65 wk of age, respectively, due to severe depressions in egg production. Egg production and egg mass for hens fed HAP diets were not different (P > 0.05) from those of hens fed the 0.45% AP diet; however, hens fed the unsupplemented HAP diet did have lower hen body weights and feed intake (P < 0.05) compared to hens fed the positive control diet. Our results indicate that HAP corn contains more available P than normal YD corn and that hens can be fed HAP corn-soybean meal diets containing little or no P supplementation with only minimal effects on production performance.

Animal Feed↗

PubMed2002

Effects of age on nutrient digestibility in chicks fed different diets.

Three experiments were conducted to determine the effects of age on apparent MEn and apparent amino acid (AA) digestibility of various diets for New Hampshire x Columbian (Experiments 1 and 2) and commercial broiler (Experiment 3) male chicks. Excreta were collected at 0 to 2, 3 to 4, 7, 14, and 21 d of age in all experiments, and nutrient digestibility was determined using acid-insoluble ash as a marker. The first experiment evaluated a corn-soybean meal (SBM) diet. Both MEn and digestibility of AA increased with age, and broken-line regression analysis predicted a plateau at 14 d for MEn and 10 d of age for AA digestibility. For example, MEn increased from 2,970 to 3,430 kcal/kg DM, and lysine digestibility increased from 78 to 89% between 0 and 14 d of age. The second experiment evaluated cornstarch-crystalline AA, dextrose-casein, corn-SBM, and corn-canola meal diets. The MEn of the corn-SBM, corn-canola meal, and cornstarch-crystalline AA diets increased from 0 to 14 d of age. In contrast, the MEn of the dextrose-casein diet was high (3,800 kcal/kg DM) immediately after hatching and did not increase substantially with increasing age. Digestibility of AA increased with age for the corn-SBM and corn-canola meal diets, and broken-line regression analysis again predicted a plateau at approximately 10 d of age. Conversely, AA digestibility of the dextrose-casein and cornstarch-crystalline AA diets was high immediately after hatching (93 to 96%) and increased only slightly with age. The results of Experiment 3 with commercial broiler chicks also showed significant (P < 0.05) increases in MEn and AA digestibility with increasing age. The results of this study indicated that the MEn and AA digestibility of corn-SBM and corn-canola meal diets increase with age for young chicks. The results also showed that MEn and AA digestibility were very high for a dextrose-casein diet immediately after hatching. Thus, the latter ingredients may have beneficial effects for very young chicks.

Aging↗

PubMed2002

Ideal ratio (relative to lysine) of tryptophan, threonine, isoleucine, and valine for chicks during the second and third weeks posthatch.

Six bioassays were conducted to determine the ideal ratios of several amino acids relative to Lys. Young male crossbred chicks were fed diets based on corn gluten meal and synthetic amino acids that could be made singly deficient in Lys, Trp, Thr, Ile, or Val. Diets for all assays contained 3,400 kcal ME/kg, and L-glutamic acid was used to make all diets (within and among assays) equal in crude protein at 22.5% of the diet. True digestibility assessment of corn gluten meal in cecectomized roosters facilitated dose-titration studies so that least squares fitted one-slope broken-lines and quadratic regression equations could be calculated to establish inflection points for weight gain and gain:feed. Four battery pens of four chicks were fed one of six amino acid levels from 8 to 21 or 22 d posthatching. Weight gain and gain:feed responded quadratically (P < 0.01) to increasing doses of digestible Lys (0.68 to 1.28%), Trp (0.09 to 0.24%), Thr (0.41 to 0.81%), Ile (0.45 to 0.95%), and Val (0.51 to 1.06%). Broken-line least squares analysis predicted breakpoints for gain and gain:feed, respectively, of: Lys (0.85, 0.96%), Trp (0.16, 0.16%), Thr (0.53, 0.53%), Ile (0.59, 0.58%), and Val (0.74, 0.74%). The intercept of the quadratic regression curve and the plateau of the broken line predicted digestible Lys requirements for gain and gain:feed, respectively, of 0.95 and 1.03%. Similar calculations predicted digestible Trp requirements of 0.18% for gain and gain:feed, digestible Thr requirements of 0.59% for gain and 0.60% for gain:feed, digestible Ile requirements of 0.68% for gain and gain:feed, and digestible Val requirements of 0.81% for gain and 0.82% for gain:feed. Regardless of curve-fitting method, gain:feed requirements for Lys were much higher than weight gain requirements. Using the higher of the broken-line requirement estimates for gain and gain:feed, ideal ratios (% of Lys) were as follows: Lys (100), Trp (16.6), Thr (55.7), Ile (61.4), and Val (77.5).

Amino Acids, Essential↗

PubMed2002

Effect of fasting versus feeding oasis after hatching on nutrient utilization in chicks.

Two experiments were conducted to determine the effects of fasting, feeding Oasis, or feeding a corn-soybean meal (SBM) or dextrose-casein diet immediately after hatching on growth performance, MEn and apparent amino acid (AA) digestibility. In each experiment, five or six pens of eight chicks were assigned to one of five treatments: feeding a corn-SBM or dextrose-casein diet immediately after hatching, fasting for 48 h (no feed or water) after hatching, or feeding Oasis for 24 or 48 h (no water) after hatching. The fasting and feeding Oasis treatments were followed by feeding the corn-SBM diet for 21 d. Excreta were collected at 0 to 2, 3 to 4, 7, 14, and 21 d on feed for determination of MEn and AA digestibility. Fasting chicks for 48 h posthatching significantly depressed weight gains compared to all other treatments at 21 d of age. Although weight losses were not significantly different at 48 h posthatching, chicks fed Oasis for 48 h had significantly (P < 0. 05) higher weight gains at 1 and 3 wk of age than did chicks fasted for 48 h. Chicks fed the dextrose-casein diet had significantly (P < 0.05) higher weight gains at 48 h and 7 d posthatching than chicks fed the corn-SBM diet immediately after hatch in Experiment 2. As time on feed increased from 3 to 21 d, MEn increased substantially (25%) for all the treatments in which chicks were fed the corn-SBM diet. In addition, the MEn of the corn-SBM diet for chicks fed Oasis was significantly (P < 0.05) higher for than chicks fasted for 48 h. The MEn of the dextrose-casein diet was high immediately after hatching and increased only slightly (2%) with increasing age. Digestibility of most AA increased with increasing age for all the corn-SBM treatments, and the digestibility values were similar among treatments. However, AA digestibility values for the dextrose-casein diet were consistently high at all ages and much higher (P < 0.05) than the other dietary treatments. Our results indicated that feeding Oasis (compared to fasting) had a beneficial effect on growth performance and subsequent energy utilization of a corn-SBM diet and that Oasis may stimulate early gut development even though very early growth (0 to 48 h) is not affected.

Animal Feed↗

PubMed2002

Effects of age on development of digestive organs and performance of chicks fed a corn-soybean meal versus a crystalline amino acid diet.

Changes in growth performance and physical and morphological development of the digestive organs were examined in chicks fed a crystalline amino acid (AA) diet compared to chicks fed a corn-soybean meal (SBM) diet. Six pens of eight New Hampshire x Columbian male chicks were assigned to one of three dietary regimens: (1) corn-SBM diet from 0 to 21 d of age; (2) cornstarch-crystalline AA diet from 0 to 21 d of age; and (3) corn-SBM diet from 0 to 7 d of age followed by the crystalline AA diet from 8 to 21 d of age. Weight gain was significantly reduced by feeding a crystalline AA diet from 0 to 21 or 8 to 21 d of age. Feeding a crystalline AA diet for the first 7 d of age depressed absolute weight of the small intestine, pancreas, liver, gizzard, and proven-triculus, and continual feeding through 21 d of age further depressed growth of these organs compared with birds fed a corn-SBM diet for 21 d. When expressing organ weight on a relative basis (g/100 g of BW), reductions were observed at 7 d of age due to feeding a crystalline AA diet but not at 21 d of age. Feeding a crystalline AA diet for the first 7 or 21 d of age depressed intestinal villi height and crypt depth. However, chicks fed the crystalline AA diet only from 8 to 21 d of age had further depressed villi height and crypt depth but greater villi width compared with chicks fed the crystalline AA or corn-SBM diet continually from 0 to 21 d of age. These results indicate that the reduced growth of chicks fed a crystalline AA diet is due in part to slower growth and development of the gastrointestinal tract.

Aging↗

PubMed2001

Efficacy of phytase for increasing protein efficiency ratio values of feed ingredients.

Data previously reported in several studies have suggested that phytase improves amino acid digestibility in chicks. It was the objective of the current study to determine if phytase would increase the protein efficiency ratio (PER) values (g weight gain per g protein intake) for several feed ingredients fed to chicks. Six experiments were conducted and ingredients evaluated were casein, soybean meal, canola meal, cottonseed meal, peanut meal, wheat middlings, wheat bran, rice bran, defatted rice bran, meat and bone meal, and corn gluten meal. Casein was evaluated to serve as a phytate-free control ingredient. Each feedstuff was analyzed for CP and included in cornstarch:dextrose diets as the only source of protein to provide 10% dietary protein in Experiments 1 to 5 or 18% dietary protein (soybean meal) in Experiment 6. Dietary Ca and nonphytate P levels were varied among experiments and ranged from 0.95 to 1.5% Ca and 0.35 to 0.675% nonphytate P. The test ingredient diets were fed with 0 or 1,200 units of phytase/kg to New Hampshire x Columbian chicks from 8 to 17 or 20 d of age. The PER values varied greatly among ingredients, ranging from 1.4 for corn gluten meal to 4.2 for canola meal. Phytase addition had no significant effect (P > 0.10) on PER values for any of the ingredients evaluated, except for an increase for casein in one experiment. The results indicated that 1,200 U of phytase/kg did not significantly increase protein utilization of several feed ingredients as assessed by a PER chick growth assay.

6-Phytase↗

PubMed2001

Early postmolt performance of laying hens fed a low-protein corn molt diet supplemented with spent hen meal.

We used a total of 504 commercial Single Comb White Leghorn hens (69 and 65 wk of age) in each of two experiments, and hens were induced to molt by feed withdrawal only. Feed withdrawal lasted for 12 and 11 d, and hens lost 26 and 25%, body weight in Experiments 1 and 2, respectively. All hens were then weighed, and seven replicate groups of 12 hens each were assigned to molt diet treatments. In Experiment 1, diets consisted of a corn basal diet (7.9% CP) or corn basal diet supplemented with 7.5 or 10% spent hen meal (SHM) each from two different sources. In Experiment 2, the corn basal diet or this diet supplemented with 5 or 10% SHM alone or 5% SHM plus Met, Lys, and Trp was evaluated. A molt diet of 16% CP corn-soybean meal was used as a positive control in both experiments. Molt diets were fed for 15 d in both experiments, at which time all hens were fed a 16% CP layer diet. Performance was measured for 8 wk following the beginning of feeding the layer diet. Feeding the low-protein corn molt diet supplemented with 5 to 10% SHM improved early postmolt egg production performance and body weight gain compared with hens fed the corn basal diet alone. The 7.5 and 10% SHM diets yielded early postmolt performance that was not significantly different (P > 0.05) from that of hens fed the high-protein (16% CP) diet. Supplementing the 5% SHM diet with amino acids generally did not significantly improve performance. The present study thus indicates that improved early postmolt performance may be achieved by supplementation of a low-protein corn molt diet with 5 to 10% SHM.

Animal Feed↗

PubMed2001

Effect of ash content on protein quality of meat and bone meal.

The effect of ash concentration on amino acid (AA) composition, true AA digestibility, and protein efficiency ratio (PER; weight gain per unit of protein intake) of meat and bone meal (MBM) was evaluated. Commercially rendered MBM samples containing 16 to 44% ash were obtained from two sources. Additional samples of MBM varying in ash from 9 to 63% were obtained by chloroform floatation or lab screening of a beef crax sample. Protein quality of selected MBM samples was assessed by determining true AA digestibility using the precision-fed cecectomized rooster assay and by a PER chick growth assay wherein chicks were fed 10% CP diets containing a MBM as the only source of dietary protein from 8 to 18 d of age. Increases in Ala, Pro, Gly, and Arg as a percentage of CP were observed in all MBM samples as ash percentage increased, with Pro and Gly accounting for most of the increase. In contrast, the levels (% of CP) of all essential AA, other than Arg, decreased as ash level increased. For example, Lys concentrations per unit of CP decreased from 5.7 to 4.0% as ash increased from 9 to 63%. There was little or no effect of ash content on AA digestibility of MBM varying in ash from 9 to 44%. The PER of MBM markedly decreased from 3.34 to 0.72 as ash increased from 16 to 44%, and most of the effects of ash on PER were not due to differences in dietary Ca and P levels. The results indicate that the reduction in protein quality of MBM as ash content increases is almost entirely due to a decrease in analyzed essential AA per unit of CP, not a decrease in digestibility of AA.

Amino Acids↗

PubMed2001

The effect of citric acid on the calcium and phosphorus requirements of chicks fed corn-soybean meal diets.

Data previously reported from our laboratory indicated that supplementation of a corn-soybean meal diet with citric acid improves P utilization in chicks. The four experiments reported herein were conducted to further evaluate the effects of citric acid on Ca and P utilization for chicks fed a corn-soybean meal diet. Diets in all experiments were fed to chicks from 8 to 21 or 22 d of age. The first experiment evaluated the effect of 6% citric acid on the Ca requirement of chicks. A Ca-deficient basal diet [23% CP, 0.54% Ca, 0.45% available P (AP)] containing 0 to 0.7% supplemental Ca in 0.1% increments was fed with or without 6% citric acid. The results indicated that citric acid did not significantly affect the Ca requirement. A second experiment evaluated different levels of citric acid (0, 2, 4, or 6%) on P utilization, and results indicated that 4 and 6% citric acid produced the largest responses in growth and tibia ash. Experiments 3 and 4 were then conducted to determine whether 4 or 6% citric acid would reduce the level of supplemental P required. Dietary treatments were a P-deficient basal diet (23% CP, 1.0 or 1.3% Ca, 0.20% AP) supplemented with 0 to 0.25% inorganic P with or without 4 or 6% citric acid. When diets contained citric acid, weight gain and tibia ash were maximized at lower AP levels than when diets contained no citric acid. The results of this study indicate that citric acid increases P utilization in corn-soybean meal diets and reduces the AP requirement by approximately 0.10% of the diet.

Animal Feed↗

PubMed2000

Nutritional evaluation of low phytate and high protein corns.

Three chick experiments and two cecectomized rooster experiments were conducted to determine P bioavailability and amino acid (AA) digestibility in two low phytate corns (LP), a high protein corn (HP), and a corn containing both low phytate and high protein content (HP/LP) compared with conventional corn (CONV). From 8 to 20 or 21 d of age, 1-wk-old New Hampshire x Columbian chicks were fed a cornstarch-dextrose-soybean meal (SBM) basal diet containing 0.10% available P or the basal diet supplemented with two concentrations of P (0.05 or 0.06% and 0.10 or 0.12%) from KH2PO4 or two concentrations of the corns (20 or 21% and 40 or 42%). Bioavailability of P based on tibia bone ash was much higher for LP than for CONV; values ranged from 21 to 40% for CONV and from 59 to 95% for LP. Digestibility of AA in cecectomized roosters indicated no significant differences (P > 0.05) between CONV and HP in the first rooster experiment. Digestibilities of eight AA, including lysine, methionine, and arginine, in LP and HP/LP were higher (P < 0.05) than those in CONV in the second rooster experiment. The results of this study indicated that the P in LP was two to three times more bioavailable than the P in CONV and that the digestibilities of AA in HP/LP were equal to or higher than those in CONV.

Amino Acids↗