Research Note: Effect of dietary cottonseed meal and soybean oil concentration on digesta passage time and amino acids digestibility in roosters

Effects of carriers for oils in compound feeds on growth performance, nutrient digestibility, and gut microbiota in broiler chickens

Carrier materials for oils in compound feeds may be used in animal nutrition to supply liquid feed additives. However, implications of such carriers for the digestibility of the contained oil are unknown. This study investigated the potential of oil carriers in compound feed and their effect on performance, metabolizable energy, fatty acid (FA) retention, amino acid (AA) digestibility, and gut microbiota in broiler chickens. Six experimental diets were formulated following a 2 × 3 factorial arrangement with 20 g/kg or 40 g/kg of rapeseed oil supplied with no carrier or bound in a silica-based (SC) or lignocellulose-based (LC) carrier in a 1:1 mass ratio. The diets were assigned to 48 metabolism units with 15 animals each based on a randomized complete block design and fed from d 18 to 28 of the trial. Total excreta were collected from d 24 to 27 and used to determine total tract retention (TTR) of FA and MEn. On d 28, AA digestibility both by the distal half of the jejunum and the distal half of the ileum was determined, and microbiota of ileal and cecal digesta was analyzed using 16S ribosomal RNA sequencing. There were significant interactions for ADG, ADFI, the gain:feed ratio (G:F), MEn, and the TTR of crude fat and most fatty acids (P ≤ 0.046) except for C18, C18:2, and C22:0. Addition of SC decreased ADG, ADFI, and G:F (P < 0.001), while LC at 40 g/kg oil inclusion increased G:F and MEn (P < 0.001) for both inclusion levels. The TTR of crude fat and the FA C18:1, C18:2, C18:3, and C22:0 was increased by the addition of SC (P ≤ 0.016), while LC increased the TTR of the FA C18:1 and C18:2 as well as the TTR of C18:3 at 20 g/kg oil inclusion (P ≤ 0.016). Adding SC and LC increased the digestibility of 7 and 2 AA by the distal half of the jejunum, respectively, and the digestibility of 8 and 13 AA by the distal half of the ileum, respectively (P ≤ 0.039). The β-diversity and abundance of some taxa were altered by addition of LC and SC in the ceca while no treatment effect on the ileal microbiota was found. The results give no indication of an incomplete release of the oil from the carriers because the TTR of most FA was increased upon addition of SC and LC. LC may be used to supply liposoluble feed additives without drawbacks for nutrient digestibility and growth while SC requires further examination.

In vitro release and in vivo growth-promoting effects of coated cysteamine in broilers

The purpose of this study was to investigate the effects of coating technology on the cysteamine (CSH) release in the digestive tract and the growth-promoting effect of enteric-coating CSH in broilers. First, using the self-developed computer-controlled simulated digestion system to mimic the digestion process in vitro, the release of 2 coated CSH (CSH-I and CSH-Ⅱ) were studied. The results showed that less than 10% of CSH-I was released after gastric digestion and 52.35% of CSH-I was released with additional 4 h of small intestinal digestion. In contrast, 83.62% of CSH-Ⅱ was released during the gastric digestion. In order to verify the growth-promoting effects of CSH-I, a feeding trial was conducted in a completely randomized block arrangement with 3 treatments in 6 blocks, 5 chickens per replicate. Broilers were fed with corn-soybean meal diet either supplemented with 0 (CON), 200 mg/kg uncoated CSH (CSH) or 200 mg/kg CSH-I from d 7 to 42, respectively. Body weight and FI was recorded at d 21 and 42. Excreta were collected from d 39 to d 42 to determine the total tract retention (TTR) of dietary nutrients. In comparisons with controls, birds fed with CSH-I had greater BW, ADG, and ADFI and increased TTR of DM, gross energy (GE), NDF and hemicellulose (P < 0.05). In addition, duodenal villi height and surface area were also greater in those CSH-I-fed birds. In contrast, the growth performance of birds fed with uncoated CSH did not significantly differ from controls. Although the TTR of DM and GE was higher in birds fed with CSH than controls, no differences in small intestine morphology were noted. Thus, the type I coating (CSH-I) could be good enteric-coating technology to increase CSH release in the duodenum, improve digestion and duodenal morphology, and therefore growth performance in broilers.

Comparison of amino acid digestibility and its additivity determined with slaughter or cecectomy method for yellow-feather chicken

The objective of this experiment was to compare the slaughter and cecectomy methods to determine amino acid (AA) digestibility of corn and soybean meal and their additivity in a corn-soybean meal diet. A completely randomized design was adopted to determine endogenous AA losses (EAAL) and AA digestibility in each of corn, soybean meal, and a corn-soybean meal diet using either slaughter or cecectomy methods. Each treatment contained 6 replicates with 3 chickens per replicate. The endogenous loss (EL) of histidine and glycine was lower and the EL of methionine and phenylalanine was greater when determined by slaughter vs. cecectomy (P < 0.05). The EL of arginine, isoleucine, leucine, lysine, methionine, phenylalanine, valine, alanine, aspartic acid, glutamic acid, and serine determined by slaughter were 1.2 to 3.2 times of those from cecectomy. The standard error (SE) of EL of 14 AA (excluding histidine and glycine) obtained by slaughter method was 2.1 to 9.6 times of those by cecectomy method. The apparent and standardized digestibility was not affected by methods for most AA except apparent digestibility of methionine, phenylalanine and glycine, and standardized digestibility of glycine in corn. The apparent and standardized digestibility of most AA except apparent digestibility of glycine and standardized digestibility of lysine, cysteine and glycine were less for slaughter versus cecectomy methods in soybean meal (P < 0.05). Using slaughter method resulted in reduced apparent digestibility of 15 AA (except glycine) and reduced standardized digestibility of 7 AA (arginine, isoleucine, leucine, valine, aspartic acid, glutamic acid, and proline) relative to cecectomy method (P < 0.05), but the standardized digestibility of glycine was greater when determined by slaughter vs. cecectomy methods in corn-soybean meal diet (P < 0.05). The mean value of SE of 16 AA digestibility in slaughter method was 2.9 times of that by cecectomy method. The apparent digestibility of 2 and 9 of 16 AA and the standardized digestibility of 15 and 7 of 16 AA were additive when using slaughter and cecectomy determinations, respectively. In conclusion, compared to the slaughter method, cecectomy method had less SE and EAAL but greater apparent digestibility of methionine and phenylalanine in corn, and the apparent digestibility of 15 AA (except glycine) in soybean meal and corn-soybean meal diet. Additivity in apparent and standardized AA digestibility was more inconsistent when determined with slaughter vs. cecectomy methods. These findings suggest that the cecectomy method is more suitable than the slaughter method to determine the digestibility of AA.

Bacillus subtilis ANSB168 Producing d-alanyl-d-alanine Carboxypeptidase Could Alleviate the Immune Injury and Inflammation Induced by Ochratoxin A

Ochratoxin A (OTA) is toxic to animals and threatens food safety through residues in animal tissues. A novel degrading strain Bacillus subtilis ANSB168 was isolated and further investigated. We cloned d-alanyl-d-alanine carboxypeptidase DacA and DacB from ANSB168 and over-expressed them in Escherichia coli Rosetta (DE3). Then, we characterized the OTA degradation mechanism of DacA and DacB, which was degrading OTA into OTα. A total of 45 laying hens were divided into three equal groups. The control group was fed basal feed, and other groups were administered with OTA (250 μg/kg of feed). A freeze-dried culture powder of ANSB168 (3 × 10⁷ CFU/g, 2 kg/T of feed) was added to one of the OTA-fed groups for 28 days from day one of the experiment. We found that OTA significantly damaged the kidney and liver, inducing inflammation and activating the humoral immune system, causing oxidative stress in the layers. The ANSB168 bioproduct was able to alleviate OTA-induced kidney and liver damage, relieving OTA-induced inflammation and oxidative stress. Overall, DacA and DacB derived from ANSB168 degraded OTA into OTα, while the ANSB168 bioproduct was able to alleviate damages induced by OTA in laying hens.