Research Note: Intestinal morphology and gene expression changes in broilers supplemented with lysolecithin.

Lysolecithin is used as a feed additive to aid fat digestion and absorption in broiler chickens. Previous research has shown that dietary fat source influences how broilers respond to lysolecithin supplementation. Therefore, the objective of this study was to investigate the effect of lysolecithin on a diet formulated with soybean oil on jejunum morphology and expression of selected genes in broiler chickens. Male Cobb 500 chickens were fed a Control diet or the Control diet supplemented with lysolecithin (TRT) from day of hatch to day 28. Jejunal samples were collected at day 10 for morphological and gene expression analysis. Feeding the TRT diet did not affect BW, villus height (VH), crypt depth (CD) or VH/CD ratio compared to Control fed chickens. Differential gene expression in the jejunum was analyzed using a custom microarray. Using a t test, 36 genes were found to be upregulated in TRT fed chickens compared to chickens fed the Control diet. The two most upregulated genes were carbonic anhydrase VII and interleukin 8-like 2, which are associated with healthy intestines. In summary, lysolecithin supplementation in a diet formulated with soybean oil caused no morphological changes but upregulated a number of genes in the jejunum.

Changes with age in density of goblet cells in the small intestine of broiler chicks.

Goblet cells secrete mucin 2 (Muc2), which is a major component of the mucus that lines the intestinal tract and creates a protective barrier between pathogens and the intestinal epithelial cells and thus are important for chick health. The objectives of this study were to determine the age-specific and intestinal segment-specific expression of Muc2 mRNA and changes in the number of goblet cells from late embryogenesis to early after hatch. Small intestinal samples from the duodenum, jejunum, and ileum were collected from Cobb 500 broilers at embryonic day 19 (e19), day of hatch (doh), and day 2 and 4 after hatch. Cells expressing Muc2 mRNA and mucin glycoprotein were detected by in situ hybridization or alcian blue and periodic acid-Schiff staining, respectively. Along the villi, there were many more cells expressing Muc2 mRNA than those stained for mucin glycoprotein. In the crypt, cells expressing Muc2 mRNA did not stain for mucin glycoprotein. There was an increase in the density of goblet cells in the villi and Muc2 mRNA expressing cells in the crypts of the jejunum and ileum from e19 to doh and day 2 to day 4, with no change between doh and day 2. In contrast, in the duodenum, the density of goblet cells in the villi and Muc2 mRNA expressing cells in the crypts remained constant from e19 to day 4. At day 4, the villi in the ileum had a greater density of goblet cells than the duodenum. In the crypt, the ileum had a greater density of Muc2 mRNA expressing cells than the duodenum at doh, and the ileum and jejunum both had greater densities of Muc2 mRNA expressing cells than the duodenum at day 4. These results indicate that the population of goblet cells has reached a steady state by doh in the duodenum, whereas in the jejunum and ileum, a steady-state population was not reached until after hatch.

Effects of dietary amino acid density and feed allocation during the starter period on 41 days of age growth performance and processing characteristics of broiler chickens given coccidiosis vaccination at hatch1.

A study was conducted to determine if increasing digestible (dig) amino acid (AA) density or feed allocation of starter diets fed to broilers receiving coccidiosis vaccination can ameliorate poor cumulative growth performance and reduce meat yield. A total of 1,600 Yield Plus Ross × Ross 708 male broilers were assigned to a 2 × 3 factorial arrangement of dig AA density [moderate (1.15% dig Lys) and high (1.25% dig Lys)] and feed allotment (0.45, 0.73, and 1.00 kg/bird) with 2 positive control treatments during the starter period. Diets were formulated to essential AA ratios relative to dig Lys. Vaccinated birds received a 1x dosage of Coccivac- B52 prior to placement, whereas non-vaccinated birds in the positive control groups were fed diets containing diclazuril. Following consumption of the starter diets, birds were provided common grower and finisher diets. Broilers fed the high AA density diet during the starter period had higher cumulative BW gain and lower cumulative feed conversion ratios (P < 0.05) than those fed the moderate AA density diet. Broilers fed the high AA density diet had heavier (P ≤ 0.005) carcass and total breast weights than birds fed the moderate AA density diet. Broilers fed a starter allotment of 1.00 kg/bird produced heavier carcass weights (P ≤ 0.006) than did birds provided lower allotments. Additionally, broilers fed the high AA density diet had a greater percentage of 0 scores (P = 0.005) for the upper intestinal region during scoring. Results from this study indicated that feeding the high AA density diet at higher feed allotments during the starter period resulted in increased AA intake, which supported the bird through the vaccine challenge and enhanced the cumulative growth and meat yield.

Effects of pre-starter and starter diets varying in amino acid density given to broiler chickens that received coccidiosis vaccination at hatch1.

An experiment was conducted to evaluate broilers vaccinated against coccidiosis fed combinations of pre-starter and starter diets varying in digestible amino acid (dAA) density from 1 to 19 d of age on subsequent growth performance and meat yield. A total of 1,800 Yield Plus Ross × Ross 708 male broilers were allocated to 60 floor pens and assigned to 1 of the 6 treatments. Four pre-starter diets varying in dAA density [1.15% dLys, 1.25% dLys, 1.35% dLys, and Positive Control (1.15% dLys + Diclazuril)] were fed until 9 d of age. Then, 3 starter diets varying in dAA density [1.15% dLys, 1.25% dLys, and PC (1.15% dLys + Diclazuril)] were given from 10 to 19 d of age. All diets were formulated to similar dAA ratios to dLys; hence, resulting in increasing amino acid (AA) density among the dietary treatments. Birds were given common grower and finisher diets for the remainder of the experiment. At 19, 27, and 40 d of age, broilers that received the 1.35% and 1.25% dLys density pre-starter and 1.25% dLys density starter diets had increased BW gain (P ≤ 0.006) compared with broilers fed the 1.15% dLys density diets. Broilers that received the 1.15% dLys density pre-starter diet had a lower cumulative BW gain (P = 0.007) than those fed the 1.35% and 1.25% dLys density pre-starter diets. Broilers that received the 1.35% and 1.25% dLys density pre-starter and 1.25% dLys density starter diets had the heaviest (P ≤ 0.008) total breast weights. Increasing the pre-starter dAA density enhanced (P ≤ 0.03) total breast weight by 28 g (1.25% dLys density) and 51 g (1.35% dLys density). Results from this study indicated that increasing dAA density from 1 to 19 d of age enabled a 1 to 19 d dAA intake increase of 4.8 g, which enhanced cumulative growth and meat yield of broilers vaccinated against coccidiosis.

Calcium and phosphorus loss from laying hen bones autoclaved for tissue removal.

Standard procedure for most conventional bone assays rely on bones being free of attached muscle or integumentary tissue. Use of an autoclave for bone cleaning is advantageous, as parts may be cleaned afterward by peeling the muscle away as opposed to tediously scrapping muscle tissue from the bone by hand. However, autoclave use for tissue removal has not been validated and published studies typically do not specify the cleaning method. One concern is that autoclave usage could cause mineral leaching out of the bone. The objective was to determine any change in bone mineral content as a result of autoclaving bone samples to remove muscle tissue. Ten pairs of frozen chicken legs were randomly selected and thawed from 72-wk-old W36 hens. Right legs were autoclaved at 121°C for 25 min in individual trays. Left legs were thawed and cleaned by hand. The tibia, meat, and exudate were collected from each leg. Cleaned bones were placed in a soxhlet to extract the fat for 30 h and ashed at 600°C for 8 h. Bone and muscle samples underwent microwave digestion in 10 mL of 70% nitric acid. Digested samples were analyzed for calcium using a flame atomic absorption spectrophotometer. Phosphorus was determined by a colorimetric assay measuring phosphate ion complexes. Statistical analysis was completed by paired t-tests. We found no significant calcium (P = 0.6319) or phosphorus (P = 0.1698) loss from bones autoclaved as compared with bones that were hand cleaned. This study provides evidence that affirms that the use of the autoclave on bones is a suitable method for tissue removal from the leg bones of adult laying hens.