Dietary supplementation of 25-hydroxycholecalciferol increases tibial mass by suppression bone resorption in meat ducks

Leg problems often result from the rapid weight gain and poor bone quality in modern ducks,leading to a high risk of fractures and continuous pain.We hypothesized that improving bone quality in combination with delaying weight gain via a low nutrient density(LND)diet probably reverses these skeletal abnormalities.Studies indicated that 25-hydroxycholecalciferol(25-OH-D3),a vitamin D3 metabolite,is effective in treating bone-related disorders.Therefore,Exp.1 evaluated the effects of 25-OH-D3 on tibial mass of meat ducks.Male meat ducklings were fed a standard nutrient density diet(containing a regular vitamin regimen)without or with 25-OH-D3 at 0.069 mg/kg for 35 d.The results showed that 25-OH-D3 supplementation improved the mineral content,microarchitecture and mechanical properties of tibias,and this companied by a decreased serum bone resorption marker and a concomitant decrement in osteoclast-specific marker genes expression.Subsequently,Exp.2 was conducted to examine the impacts of 25-OH-D3 incorporating an LND diet on tibial quality of ducks under 2 different vitamin regimens(regular and high).Ducklings were allocated to a 2*2 factorial arrangement with 2 kinds of vitamin premixes and without or with 25-OH-D3 at 0.069 mg/kg in LND diets.The high premix had higher levels of all vitamins except biotin than the regular premix.The results demonstrated that high vitamin diets exhibited more significant effects than regular vitamin diets on inhibiting bone turnover and increasing minerals deposition.Tibial mineral content,microarchitecture,and strength of birds under the regular vitamin regimen were increased by 25-OH-D3 supplementation;However,these positive effects were not observed in ducks under the high vitamin regimen.To conclude,25-OH-D3 supplementation improves tibial mass by suppressing osteoclast-mediated bone resorption in meat ducks,and this positive impact only was observed in regular but not high vitamin regimen when birds fed an LND diet.

Effects of dietary nanocrystalline cellulose supplementation on growth performance,carcass traits,intestinal development and lipid metabolism of meat ducks

The influence of nanocrystalline cellulose(NCC) supplementation on growth performance, carcass traits,intestinal development, and lipid metabolism was assessed in 600 one-day-old male meat ducks(Cherry Valley ducks) from 1 to 35 d of age. Diets were supplemented with 0,200,500,800 and 1,500 mg/kg NCC during both the starter(1-14 d) and grower(15-35 d) phases. Each dietary treatment consisted of 8 replicate cages of 15 birds. Supplementation of NCC was associated with dose dependent increases in BW gain and feed intake(P < 0.01) during 1-14 d of age and in BW at 35 d of age. As NCC content increased,the percentage of breast meat weight(P < 0.05) and leg(with bone) weight(P < 0.05) linearly increased,while the percentage of abdominal fat weight(P < 0.01) linearly decre.ased in ducks at 35 d of age.Supplementation of NCC resulted in a dose-dependent increase in the weight(P < 0.05) and density(P < 0.01) of the cecum. The percentage of total hepatic lipid content(P < 0.01) at 14 d of age and serum triglyceride(TG) concentration(P = 0.052) at 35 d of age linearly decreased with increasing of dietary NCC addition. In conclusion, inclusion of 1,500 mg/kg NCC in feed resulted in the greatest improvements in duck performance, intestinal development and lipid deposition.

Calcium supplementation in low nutrient density diet for meat ducksimproves breast meat tenderness associated with myocyte apoptosisand proteolytic changes

To define the relationship between dietary nutrient density, calcium (Ca), and meat quality in meatducks. A total of 288 male Cherry Valley SM3 medium ducklings were fed a common standard starter dietuntil d 14. At 15 d of age, ducks were randomly divided into 2 treatment groups and fed either a conventionaldiet or a low nutrient density (LND) diet. Compared with the conventional diet, the energy wasreduced in the LND diet by 8.6% and 16.8% in grower (15 to 35 d) and finisher (36 to 56 d) phases,respectively, while other essential nutrients were kept proportionate to energy. The LND diet decreasedthe shear force (P < 0.05) and increased the lightness values of the pectoralis muscle when compared tothe conventional diet, suggesting that LND diet exerted a beneficial role in meat quality. Subsequently,the effects of grated Ca in the LND diet on meat quality of pectoralis muscle were evaluated. A total of 576male ducklings were fed a common starter diet until d 14, followed by feeding 4 LND diets with 0.5%,0.7%, 0.9%, and 1.1% Ca. The results show that LND diets with 0.7% or more Ca decreased the shear force ofpectoralis major muscle in 42-d-old meat ducks (P < 0.05). To explore the mechanism underlying Ca andtenderness, data from birds fed either 0.5% or 1.1% Ca in the LND diet indicated that birds fed 1.1% Caexhibited lower shear force, upregulated calpains 1 expression, and higher calpains activity compared tothose fed the LND diet with 0.5% Ca (P < 0.05). Moreover, the 1.1% Ca LND diet induced a higher myocyteapoptosis (P =0.06) and upregulated mRNA expression of caspase-3 (P =0.07) in breast muscle. Our datasuggest that LND diets with 0.9% or 1.1% Ca had a positive role in the tenderness of breast meat,particularly the enhancing effect of 1.1% Ca LND diet on tenderness seems to be associated with proteolyticchanges of myofibrillar proteins and myocyte apoptosis in meat ducks.

Effects of a multi-enzyme complex on growth performance,nutrient utilization and bone mineralization of meat duck

Background： Previous studies with broiler have shown dietary supplementation with multi-enzyme complex containing non-starch polysaccharides （NSP） degrading enzymes and phytase is efficient in releasing phosphorus （P）, calcium （Ca）, energy and amino acids from corn-soybean meal diets or corn-sorghum diets, hence compensating considerable levels of nutrients in formulation. Notwithstanding, such potentials have not been well defined in duck nutrition. Giving China being the largest duck producing country, we conducted this study to establish adequate specifications of major nutrients along with multi-enzyme complex to meat duck from day-old to slaughter, focusing on performance, utilization of nutrients and bone mineralization. Five dietary treatments were： Positive control （PC,T1）： the nutrients concentration of diet for 1 to 14 d of age were apparent metabolizable energy（AME） 2,800 kcal/kg, crude protein （CP）1 9.39%, Ca 0.85%, available phosphorus （avP） 0.42%; for 15 to 35 d of age these parameters were AME 2,900 kcal/kg, CP 16.47%,Ca 0.76%,avP 0.38%; Negative control 1（NC1,7-2）, the AME and digestible amino acids （DAA） were reduced by 70 kcal/kg and 2.0%, avP and Ca by 1.0 g/kg from PC diet; Negative control 2（NC2,T4）, the down- spec from PC diet was AME 100 kcal/kg, DAA 2.5%, avP 1.5 g/kg and Ca 1.2 g/kg; The enzyme complex was added at the same dosage （200 mL/1,000 kg） on NC1 （T3） and NC2 （T5） diets. Results： Comparing with the ducks fed on T1, T3 and T5 diets, the birds fed on NC2 diet showed the lowest （P 〈 0.05） body weight （ d 14 and 35）, feed intake （d 35）, tibia ash, Ca and P contents （d 14 and 35）, and the utilization of nutrients （P 〈 0.05）. The supplementation with the enzyme complex to the NC diets restored growth rate, utilization of nutrients and bone mineralization to the level of the PC diet, and increased AME by 60 kcal/kg and 117 kcal/kg, respectively for the NC1 and NC2 diets. Conclusion： These results suggest that down-spec AME by 100 kcal/kg, DAA by 2.5%, avP by 1.5 g/kg and Ca by 1.2 g/kg caused detrimental effects on duck performance compared with those fed on the PC diet, and these performance losses can be compensated by the addition of the multiple-enzyme complex.

Characterization of spoilage bacterial communities in chilled duck meat treated by kojic acid

Chilled duck meat is a popularly consumed meat in China but easily perishes at room/low temperature. Kojic acid is usually used as an antimicrobial. This study investigated the sensory scores, total bacteria number, and total volatile base nitrogen (TVB-N) value of chilled duck meat under kojic acid treatment during storage. The results presented that kojic acid suppressed the growth of spoilage bacteria and prolonged the shelf-life of chilled duck meat by at least two days. In further investigation, the bacterial community composition was explored through high-throughput sequencing. Pseudomonas spp. were the predominant spoilage bacteria after 6-day storage and were significantly suppressed by kojic acid. Besides, Brochothrix showed drug resistance and became the dominant bacteria in the kojic acid treated sample after 6-day storage. In conclusion, kojic acid maintained the sensorial, chemical, and microbial quality of duck meat stored at low temperatures. Meanwhile, kojic acid enriched the bacteria composition and showed strong antimicrobial activity against Pseudomonas spp.