The influence of the amylopectin/amylose ratio in samples of corn on the true metabolizable energy value for ducks

Effects of different starch structures on energy metabolism in pigs

BACKGROUND

Starch is a major component of carbohydrates and a major energy source for monogastric animals. Starch is composed of amylose and amylopectin and has different physiological functions due to its different structure. It has been shown that the energy supply efficiency of amylose is lower than that of amylopectin. However, there are few studies on the effect of starch structure on the available energy of pigs. The purpose of this study was to measure the effect of different structures of starch in the diet on the net energy (NE) of pigs using a comparative slaughter method and to establish a prediction equation to estimate the NE of starch with different structures. Fifty-six barrows (initial BW 10.18 ± 0.11 kg) were used, and they were housed and fed individually. Pigs were divided into 7 treatments, with 8 replicates for each treatment and 1 pig for each replicate. One of the treatments was randomly selected as the initial slaughter group (ISG). Pigs in the remaining treatments were assigned to 6 diets, fed with basic diet and semi-pure diets with amylose/amylopectin ratio (AR) of 3.09, 1.47, 0.25, 0.15 and 0.12, respectively. The experiment lasted for 28 d.

RESULTS

Results showed that compared with the high amylose (AM) groups (AR 3.09 and 1.47), the high amylopectin (AP) group (AR 0.15) significantly increased the final BW, average daily weight gain and average daily feed intake of pigs (P < 0.05), but the F:G of the AM group was lower (P < 0.01). In addition, AR 0.15 and 0.12 groups have higher (P < 0.01) nutrient digestibility of dry matter, crude protein, gross energy and crude ash. Meanwhile, compared with other groups, AR 0.15 group has a higher (P < 0.05) NE intake and energy retention (RE). The regressive equation for predicting with starch structures was established as RE = 1,235.243 - 48.298AM/AP (R2 = 0.657, P = 0.05).

CONCLUSIONS

In conclusion, NE intake and RE of pigs augmented with the increase of dietary amylopectin content, indicating that diets high in amylopectin were more conducive to promoting the growth of pigs in the late conservation period.

Corn kernel hardness, drying temperature and amylase supplementation affect live performance and nutrient utilization of broilers

Drying temperature (DT) of corn can influence its nutritional quality, but whether this is influenced by endosperm hardness is not clear. Two parallel experiments were conducted to investigate the effects of 2 yellow dent corn hybrids with average and hard kernel hardness, dried at 3 temperatures (35, 80, and 120°C), and 2 supplementation levels of an exogenous amylase (0, 133 g/ton of feed) on live performance, starch and protein digestibility, and energy utilization of Ross 708 male broilers. Twelve dietary treatments consisting of a 2 × 3 × 2 factorial arrangement were evaluated using 3-way ANOVA in a randomized complete block design. In Experiment 1, a total of 1,920 male-chicks were randomly allocated to 96 floor pens, whereas 480 day-old chicks were distributed among 96 cages for Experiment 2. At 40 d, interaction effects (P < 0.05) were detected on BWG, FCR, and flock uniformity. Supplementation with exogenous amylase resulted in heavier broilers, better FCR and flock uniformity, only in the diets based on corn dried at 35°C. Additionally, interaction effects were observed on FCR due to kernel hardness and DT (P < 0.01), kernel hardness and amylase supplementation (P < 0.001), and DT and amylase supplementation (P < 0.05). Exogenous amylase addition to the diets based on corn with an average hardness improved FCR up to 2 points (1.49 vs. 1.51 g:g) whereas there was no effect of amylase on FCR of broilers fed diets based on corn with hard endosperm. Total tract retention of starch was increased (P < 0.05) in broilers fed diets based on corn with average kernel hardness compared to hard kernel. Corn dried at 80 and 120°C had up to 1.21% points less starch total tract retention than the one dried at 35°C. Supplementing alpha-amylase resulted in beneficial effects for broiler live performance, energy utilization, and starch total tract digestibility results. Treatment effects on starch characteristics were explored. Corn endosperm hardness, DT and exogenous amylase can influence the live performance of broilers. However, these factors are not independent and so must be manipulated strategically to improve broiler performance.

Corn drying temperature, particle size, and amylase supplementation influence growth performance, digestive tract development, and nutrient utilization of broilers

Broiler live performance may be influenced by postharvest corn drying temperature, and results could depend on particle size after grinding. The supplementation with an exogenous amylase may improve performance parameters, but responses to enzymes are also affected by particle size. Two parallel experiments were conducted to evaluate the effects of hard-kernel corn dried at 2 temperatures (35°C and 120°C), ground at 2 particle sizes (coarse or fine), and 3 supplementation levels (0, 133, and 266 g ton-1) of an exogenous amylase on live performance, gastrointestinal organ development, energy utilization, and nutrient digestibility. Twelve dietary treatments resulting from a 2 × 2 × 3 factorial arrangement of drying temperature, particle size, and amylase supplementation were evaluated in both experiments. A total of 1,920 day-old male chicks were randomly allocated to 96 floor pens, while 480 chicks were distributed among 4 battery brooder units. Ileal and fecal samples were collected to determine energy utilization and nutrient digestibility using titanium dioxide as inert marker. At 42 D, organs were collected, and relative weight or length was determined. Data were analyzed using a three-way ANOVA in a randomized complete block design. Feeding fine corn-based diets showed improvements on live performance for both studies. At 40 D, supplementing 266 g ton-1 of amylase improved feed conversion ratio (P < 0.05) by 1 point compared to chickens that consumed nonsupplemented diets and feed with amylase at 133 g ton-1. Broilers fed coarse corn-based diets had heavier gizzard (P < 0.001) and liver (P < 0.05) than chickens that consumed fine corn-based diets. In addition, starch digestibility was improved by amylase (P < 0.05) at 133 g ton-1 and by feeding coarse corn-based diets (P = 0.06). For chicks raised in cages (16 D), AMEn was increased (P < 0.01) by amylase supplementation regardless of its inclusion level. In conclusion, drying temperature and particle size interactions influenced broiler live performance, gastrointestinal organ development, nutrient digestibility, and energy utilization, and these parameters were improved by supplementing amylase.

Effects of replacing corn with sorghum on the performance of overfed mule ducks

The aim of this trial was to study the effects of replacing yellow corn (C) with condensed tannin-free sorghum (S) during the finishing period (F period; age 53 to 79 d) and/or overfeeding period (O period; age 80 to 91 d) on the performance of overfed mule ducks. 192 ducks were divided into 4 groups (48 in each) differing in the cereal (yellow corn or sorghum) included in the diet given during the F and/or the O periods, using a 2 × 2 factorial arrangement of treatments : SS, SC, CS, CC. At the end of the O period, the birds were slaughtered after 10 h of fasting to measure foie gras and magret qualities. Mortality (1%; P > 0.05) and weight gain (2,030 g; P > 0.05) during the O period were similar in the 4 groups. At the end of the O period, birds overfed with sorghum had foie gras that was heavier (723 vs. 694 g in CS+SS vs. CC+SC, respectively; P < 0.05) and less yellow (24.40 vs. 38.59 for b* in CS+SS vs. CC+SC, respectively; P < 0.001) than birds overfed with corn. Fat loss during foie gras cooking was similar in the 4 groups (18%; P > 0.05), but the foie gras was less yellow in birds overfed with sorghum (14.84 vs. 26.01 for b* in CS+SS vs. CC+SC, respectively; P < 0.001). Weight of magret was similar in the 4 groups (491 g, P > 0.05) but the color of the breast muscle and skin of magret was less yellow in birds overfed with sorghum compared with corn (12.26 vs. 12.92 and 13.84 vs. 18.30 in CS+SS vs. CC+SC, respectively; P < 0.001). In conclusion, the replacement of yellow corn with sorghum during finishing and/or overfeeding is possible and useful in a mule duck foie gras production system because it increases foie gras weight without decreasing the weight of magret However, it changes the quality of the products, mainly their color.

Metabolizable energy, nitrogen balance, and ileal digestibility of amino acids in quality protein maize for pigs

BACKGROUND

To compare the nutritional value and digestibility of five quality protein maize (QPM) hybrids to that of white and yellow maize, two experiments were carried out in growing pigs. In experiment 1, the energy metabolizability and the nitrogen balance of growing pigs fed one of five QPM hybrid diets were compared against those of pigs fed white or yellow maize. In experiment 2, the apparent and standardized ileal digestibility (AID and SID, respectively) of proteins and amino acids from the five QPM hybrids were compared against those obtained from pigs fed white and yellow maize. In both experiments, the comparisons were conducted using contrasts.

RESULTS

The dry matter and nitrogen intakes were higher in the pigs fed the QPM hybrids (P < 0.05) than in the pigs fed white or yellow maize. Energy digestibility (P < 0.001) and metabolizability (P < 0.01) were higher in the pigs fed the white and yellow maize diets than in those fed the QPM diets. The AID of lysine was higher (P < 0.01) in the QPM diets than in the white and yellow maize. The AIDs of leucine, isoleucine, valine, phenylalanine, and methionine were lower in the QPM diets than those of maize (white and yellow) (all P < 0.05). Maize (white and yellow) had greater SIDs of leucine, isoleucine, valine, phenylalanine, glutamic acid, serine, alanine, tyrosine, and proline (P < 0.05).

CONCLUSIONS

Based on these results, it was concluded that QPM had a lower metabolizable energy content and a higher amount of digestible lysine than normal maize.

Effects of substituting yellow corn for sorghum in geese diets on magret and foie gras quality

The aim of this trial was to study the effects of substitution of yellow corn with sorghum during the growing-finishing (G period), overfeeding (O period), or both periods on magret and foie gras quality in geese. In total, 260 ganders were divided into 4 groups (65 birds in each) differing in the cereal (yellow corn or sorghum) included in the diet given during the G and the O periods, using a 2 × 2 factorial arrangement of treatments. The groups differed in the nature of the cereal in the diet offered to birds between 44 and 104 d of age (G period: a diet containing 500 g of sorghum/kg (SS and SC groups) or a diet containing 500 g of yellow corn/kg (CS and CC groups). The groups differed also in the diet offered to birds between 105 and 120 d of age (O period): 967 g of yellow corn/kg (SC and CC groups) or 965 g of sorghum/kg (SS and CS groups). At the end of the O period, the birds were slaughtered after 10 h of fasting to measure foie gras and breast muscle weight, color, and chemical composition. The mortality in the SC group was higher (P < 0.05) than in the other 3 groups (14.29 vs. 3.58%, average of the 3 groups). After overfeeding, birds fed with sorghum had foie gras that were heavier 984 vs. 885 g, in CS+SS vs. CC+SC groups, respectively; P < 0.001) and less yellow (18.03 vs. 23.97 for b*, in CS+SS vs. CC+SC groups, respectively, P < 0.001) than birds fed with corn. The substitution of yellow corn with sorghum during the G and O periods (SS group) increased the weight of the foie gras, but altered its color to a paler yellow. In contrast, a substitution during the G period only (SC group) resulted in increased mortality during the O period.