Effect Of Crude Protein Intake Research Articles

The effect of crude protein intake on sperm quality of young and old male broiler breeders

This experiment compared fertility of male broiler breeders with different crude protein (CP) intakes from diets containing 9.7%, 11.7% and 13% CP from 27 to 60 weeks of age (in two phases) and in a different group of birds from 52 to 60 weeks of age. This was to assess fertility of males with different CP intakes, as well as comparing fertility in older birds having been fed different protein intakes throughout production to those on a commercial ration for most of production. Sperm concentration and sperm mobility were assessed, as well as the number of points of hydrolysis in the inner-perivitelline membrane of eggs from commercial egg-type hybrids after insemination, which was used to predict egg fertility. There was no response to CP intake observed in sperm concentration or sperm mobility at any age. A positive effect of CP intake was observed in egg fertility towards the end of the production phase. While broiler breeder producers make use of separate sex feeding, the female ration is often fed to males in the appropriate amounts to achieve growth according to the target for males. However because it would be cheaper to include less CP in the ration, the effect of CP on breeder fertility is important. This experiment showed that reducing CP to 117 g/kg in male broiler breeder rations fed throughout the production phase had minimal negative effects on sperm quality, however, increasing CP intake towards the end of production may positively impact egg fertility. Keywords : Fertility, insemination, mobility, poultry

Effect of Dietary Nitrogen Content on the Urine Metabolite Profile of Dairy Cows Assessed by Nuclear Magnetic Resonance (NMR)-Based Metabolomics

NMR-based metabolomics was applied on urine samples from 32 cows that were fed four levels of crude protein (124, 135, 151, and 166 g/kg DM, respectively) in a crossover design with the aim of identifying urinary metabolites related to nitrogen intake and nitrogen efficiency. Principal component analysis (PCA) on selected regions of the obtained (1)H NMR spectra revealed an effect of crude protein intake on NMR signals in the 0.5-3.0 and 5.0-10.0 ppm regions. Partial least-squares (PLS) regressions confirmed a correlation between the NMR metabolite profile and both nitrogen intake and efficiency. The NMR signals that correlated with nitrogen intake and efficiency included urea, hippurate, phenylacetylglutamine, and p-cresol sulfate, which all contributed to the prediction of nitrogen intake and efficiency. Thus, it was not possible to identify a single metabolite that could be used as a marker to predict nitrogen efficiency, and it can be concluded that a wide-ranging urinary metabolite profile is needed to evaluate nitrogen efficiency in ruminants.

Effects of crude protein intake from forage‐only diets on muscle amino acids and glycogen levels in horses in training

There is little information about the influence of crude protein (CP) intake on glycogen and free pool amino acid concentrations in the muscle of horses in training. High energy forage-only diets may be an alternative to concentrate rich diets and may provide high levels of CP. To study the effect of feeding 2 forage-only diets, containing either high or moderate CP concentrations on glycogen and free pool amino acid concentrations in the muscle. Two high energy forage-only diets based on high-energy grass forage were fed for 23 days in a crossover design to 6 Standardbred horses in racing condition. One forage diet provided a high (HP) CP (16.6%) intake and the other diet provided recommended intake (RP) of CP (12.5%). At Day 19 a standardised treadmill test was performed to mimic a race. Blood samples were taken before, during and after (up to 90 min) the treadmill test and muscle biopsies (m. gluteus) were taken before and after exercise and after 90 min. Amino acids were analysed with a HPLC-technique and glycogen with a fluorimetric method. A main effect of the HP diet was that muscle glycogen and leucine concentrations were higher compared to the RP diet. Branched chain amino acid concentrations in plasma remained higher during early recovery from exercise on the HP diet compared to the RP diet. Intense exercise caused a similar decrease in glycogen, aspartate and glutamate concentrations in muscle and increase in alanine concentration on both diets. Feeding a forage-only diet with a high CP intake increases glycogen and leucine concentrations in muscle of horses in training. This may be beneficial for muscle recovery following intensive exercise.

Effects of crude protein intake from grass silage-only diets on the equine colon ecosystem after an abrupt feed change1

The objective of this study was to investigate the effect of CP intake from 2 grass silage-only diets, differing in CP concentration, fed at similar DMI on the equine colon ecosystem after an abrupt feed change between the diets. Four adult right ventral colon-fistulated geldings were fed one silage-only diet high in CP (HP, 873 g of CP/d) and one diet providing recommended intakes (RP, 615 g of CP/d). An adaptation period of 15 d on either the HP or the RP diet was followed by 2 experimental periods when the diets were fed for 22 d each in a crossover design. Colon samples were taken before and at 4, 12, and 24 h, and at 7, 14, and 22 d after the feed change. During the first 24 h after the abrupt feed change, the concentrations of total anaerobic bacteria and lactobacilli were greater on the HP than the RP diet (7.1 vs. 6.7 log(10) cfu/mL, P = 0.021, 6.0 vs. 5.5 log(10) cfu/mL, P = 0.021, respectively). During the first 24 h post feed change, VFA concentrations did not differ between the diets. From 7 to 22 d, total VFA concentrations were greater on the HP diet than on the RP diet (51.8 vs. 45.1 mmol/L, P = 0.034), and colon pH was lower on the HP diet than on the RP diet (6.9 vs. 7.2, P = 0.035). After an adaptation period of 22 d, N, ammonia, and urea concentrations and osmolality of the colon fluid did not differ between diets. Fecal pH and colon and fecal DM were unchanged throughout the experiment. The results suggest that, in horses fed at the maintenance level of energy intake, a feed change between silages with different CP content may alter the colon bacterial counts within the first 24 h. Moreover, during the subsequent 3 wk, pH decreased slightly and VFA concentrations increased, but no other major alterations occurred in the composition and activities of the colon ecosystem or fecal DM.

The effects of dietary protein concentration on the lactational performance of the rabbit

ABSTRACTAn experiment was performed to examine the effects of feeding four concentrations of crude protein in the diet to lactating rabbits. Diets A, B, C and D contained 173, 181, 224 and 243 g crude protein per kg dry matter respectively. Each diet was offered at one of two feeding levels: H (330 g/day) or L (280 g/day) with three replicates in each of the eight treatment groups. Milk production and nitrogen balance were measured over a 28-day lactation.Although dry-matter intakes on feeding level H were significantly higher than those on feeding level L the difference diminished as the crude protein concentration decreased. The effect of crude protein intake on doe milk production was estimated therefore by regression analysis with digestible energy intake as a covariate. Both crude protein intake and digestible energy intake alone had significant effects (P < 0·001) on daily milk production and there was also a significant effect (P < 0·05) of crude protein intake after fitting digestible energy intake. Overall the equation was:Milk production (g/day) =17·61 + 0·985 crude protein intake (g/day) + 30·3 digestible energy intake (MJ/day).(±0·448) (±14·8)The relationship between digested nitrogen and nitrogen output as milk was also examined by regression analysis with digestible energy intake as a covariate. This equation was:Nitrogen output in milk (g/day) =0·438 + 0·164 digested nitrogen (g/day) + 0·572 digestible energy intake (MJ/day).(±0·068) (±0·294)The practical implications of feeding high levels of crude protein in the diet to increase milk production and pup weaning weight are discussed.