Dietary Crude Protein Levels Research Articles

Supplementary Prebiotics, Probiotics, and Thyme (Thymus vulgaris) Essential Oil for Broilers: Performance, Intestinal Morphology, and Fecal Nutrient Composition.

This experiment was performed to evaluate the effects of selected natural feed additives (thyme extract, organic acid, probiotic, and prebiotic) on performance, intestinal morphology, and composition of fecal nutrients with two crude protein levels diet (10% reduced crude protein level and the recommended level) in broilers. In this experiment, 388 Ross-308 strain broilers from 1 to 42days in three experimental periods including starter (1 to 10days), grower (11 to 24days), and finisher (25 to 42days) were used in a completely randomized design (8 treatments, 4 replicates, and 12 chickens in 5 × 2 factorial arrangements). According to the results, use of feed additives along with both levels of crude protein had significant effects on performance, intestinal morphology, and fecal nutrient levels (P < 0.05). A 10% decrease in crude protein level of diet caused to decrease in daily weight gain and an increase in feed conversion ratio in the starting period (P < 0.05). Decreased dietary crude protein levels in growing and finishing period had insignificant effects on chicken's performance (P > 0.05). During the experiment period, the use of feed additives on diets with lower than normal crude protein levels had no effect on the average feed intake, daily weight gain, and feed conversion ratio of chickens (P > 0.05). Lower crude protein level changed the intestinal morphology (P < 0.05). The use of feed additives had significant effects on the nutrient content of feces (P < 0.05). Overall, results showed that a 10% reduction in crude protein level of diet compared to normal crude protein levels changed the intestinal morphology and nutrient content of feces while having adverse effects on the performance of chickens.

Effects of Normal and Nano-Capsulated Thyme and Peppermint Essential Oils on Intestinal Morphology and Microbial Population of Broilers Fed on Standard and Low Crude Protein Diets

This study was conducted to investigate the effects of normal and nano-capsulated forms of thyme and peppermint essential oils on intestinal morphology and microbial population of broilers fed on normal and low crude protein diets. The study was carried out with a total of 320 Ross-308 broiler chickens as a 2×2×2 (2 medicinal plant essential oils, 2 forms of oils and 2 levels of diet crude protein) factorial arrangements with 32 groups (10 chicks per replicate) according to a completely random design. This experiment was done in three periods included: Starter (1-10 days), grower (11-24 days) and finisher (25-42 days). The experimental diets had significant effects on intestinal morphology (P<0.05), so that the use of the usual form of essential oils while reducing the depth of the crypt, increased the ratio of the length of the villa to the depth of the crypt. In use of peppermint essential oil with standard protein, crypt depth increased, and the ratio of villi height to crypt depth was minimal (P<0.05). A decrease in dietary crude protein level reduced the population of lactobacilli in the intestine (P<0.05). However, the level of crude protein in the diet and the form of use of the essential oil, as well as the type of essential oil and its form, did not have significant effects on the intestinal microbial population (P>0.05). Based on the results of this experiment, it can be stated that in broilers, the use of the encapsulated form of thyme essential oil in diets with standard crude protein levels, improved the intestinal morphology and intestinal non-pathogenic microbial population of broilers. Ten percent reduction in dietary crude protein level had adverse effects on measured traits and is not recommended, and in case of reduction of dietary protein, it is necessary to use peppermint essential oils supplements.

Effect of Diet Composition on Excreta Composition and Ammonia Emissions from Growing-Finishing Pigs.

Simple SummaryPig production leads to high levels of ammonia emissions, which in turn causes environmental pollution. This paper, therefore, looks at the possibilities for reducing ammonia emissions. Reducing ammonia precursors in diets and acidifying the urine and manure pH by acidifying diets make it possible to reduce the ammonia emissions from pig production facilities. The present study tested the impact of decreased crude protein or acidifying diets on urine and manure composition and ammonia emissions from growing and finishing pig houses. We found that decreasing dietary crude protein levels reduced the ammonia emissions from the floor as well as from the pig houses, whereas acidifying diets failed to reduce ammonia emissions from the floor and the pig houses. Reducing dietary crude protein is, therefore, a positive solution to reduce ammonia emissions from pig houses.This study aimed to investigate the impact of decreased crude protein (CP) levels (by 2% units) or acidifying diets (by adding 10 g benzoic acid/kg diet in combination with replacing a part of CaCO3 by about 10 g Ca-formate/kg diet) on urine, feces and manure composition and ammonia emissions from growing and finishing pig houses. Yorkshire x F1(Landrace x Yorkshire) pigs (n = 576) with an initial body weight of 24.9 ± 3.4 kg were randomly allocated to four treatments of (i) a control diet with normal protein content and no acidifying components added; (ii) a diet with 2% units CP reduction; (iii) a diet with an acidifying effect on the manure; (iv) or a diet consisting of a combination of diet (ii) and (iii). Pigs were housed in four mechanically ventilated and temperature-controlled rooms. Results showed that decreasing the dietary CP levels by 2% units reduced the ammonia emission from the floor by 46% (p = 0.06) and from the pig house by 31% (p = 0.08). Decreased CP diets reduced the total N in feces and in manure and NH4-N in the manure, as well as the ammonia concentration at 1 cm and 10 cm above the manure surface (p < 0.05). However, acidifying diets failed to reduce ammonia emissions from the floor and the pig house (p > 0.05). Reducing dietary crude protein is, therefore, a solution to reducing ammonia emissions from pig houses.

Effect of amino acid supplementation and choline chloride for low protein diet on nitrogen efficiency and methane emission of dairy cows

Ruminants are one of the largest anthropogenic methane and nitrous oxide emissions. Therefore, the hypothesis was to study the effects of reducing dietary crude protein (CP) level on environmental contaminators when rumen-protected amino acids and choline chloride were supplemented. Sixty Holstein dairy cows were used during the experiment. Test diets were: (1) CD = Control diet with16.2 g of crude protein/ Kg of DM); (2) LM = Low protein diet with 14.2 g of crude protein/ Kg of DM + methionine ; (3) LL = Low protein diet with 14.2 g of crude protein/ Kg of DM + lysine; (4) LML = Low protein diet with 14.2 g of crude protein/ Kg of DM + methionine + lysine; (5) LMLC = Low protein diet with 14.2 g of crude protein/ Kg of DM + methionine + lysine + choline. Dry matter and NDF intake were not different, but the control group received higher CP and ADF compared with other groups (P &lt; 0.05). Fecal CP and ADF of control group were lower (P &lt; 0.05), but no differences were observed for fecal dry matter (DM) and NDF. Milk yield and protein content were higher for LML and LMLC like control group (P &lt; 0.05). Nitrogen intake, urinary N, urinary urea N and total excreta N decreased (P &lt; 0.05) when animals fed low protein. There was no difference in ruminal pH and acetate to propionate ratio, whereas the ruminal ammonia-N decreased with the low protein (P &lt; 0.05). The 120-h gas production test, showed no difference on the kinetics of digestion and in vitro methane emission. However, the inclusion of DMI in the calculations revealed that low protein can reduce (P &lt; 0.05) methane emission. Overall, our findings indicated that low protein can be compensated for by adding rumen-protected amino acids, not only to maintain the animal performance, but also to decrease nitrogen excretion and methane emission.

Effect of graded levels of dietary crude protein on nutrient utilization and enteric methane emissions in growing Murrah buffalo calves

The present study was done to investigate the effect of graded levels of dietary crude protein on enteric methane (CH4) production from Murrah buffalo calves. Fifteen Murrah buffalo male calves were divided into 5 groups (Av. BW=153.05) and were fed total mixed rations containing wheat straw, maize fodder and concentrate mixture in different proportions so that the dietary crude protein level was 5, 7.5, 10, 12.5 and 15% in groups T1,T2,T3,T4 and T5, respectively. The trial lasted for 30 days. Dry matter intake increased from 2.49 to 4.40 kg/d. Dry matter digestibility increased (P&lt;0.05) from 48.64 to 61.97%. CH4 emissions decreased (P&lt;0.05) from 34.48 to 12.73 g/kg DMI with increasing protein level in the ration. Hence, CH4 emissions were lower (12.73-12.83 g/Kg DMI) in animals fed rations containing 12.5 to 15% CP.

Effects of Different Dietary Protein Levels on the Growth Performance, Serum Biochemical Parameters, Fecal Nitrogen, and Carcass Traits of Huanjiang Mini-Pigs.

The Huanjiang mini-pig is a Chinese local breed and, the optimal dietary crude protein (CP) level for this breed is still unknown. Therefore, the present study was conducted to investigate its optimum dietary CP level upon the growth performance, serum biochemical parameters, fecal nitrogen content, and carcass traits. Three independent trials with 360 pigs were included. A total of 220 pigs (5.32 ± 0.46 kg) were fed ad libitum, either a 14, 16, 18, 20, or 22% CP diet from about 5- to 10-kg (trial 1); 84 pigs (11.27 ± 1.43 kg) were fed either a 12, 14, 16, 18, or 20% CP diet from about 10- to 20-kg (trial 2); and 56 pigs (18.80 ± 2.21 kg) were fed either a 10, 12, 14, 16, or 18% CP diet from about 20- to 30-kg (trial 3). In trial 1, as dietary CP levels increased, the feed-to-gain ratio (F/G) quadratically decreased (p < 0.05) and was minimal at the 18.42% CP level. The average daily feed intake (ADFI) and final body weight (BW) were not affected by dietary CP levels while the fat percentage decreased (p < 0.05). Besides, a linear decrease in slaughter rate (p = 0.06) and a linear increase in bone percentage (p < 0.05), serum urea nitrogen (UN) (P < 0.05), and fecal nitrogen content (p = 0.07) of pigs were observed. In trial 2, as dietary CP levels increased, the average daily gain quadratically increased (p < 0.05) and was maximum at the 16.70% CP level. The slaughter rate linearly decreased (p < 0.05) whereas the skin rate, serum UN, and NH3-N increased (p < 0.05) linearly, as well as fecal nitrogen content (p = 0.06). In trial 3, as dietary CP levels increased, the F/G increased (p < 0.05), while the ADFI and ADG quadratically decreased (p < 0.05) and was maximum at nearly 14.00% CP level. The bone percentage and serum UN increased (p < 0.05) linearly but the slaughter rate decreased (P < 0.05) linearly, and the fecal nitrogen content quadratically decreased (p = 0.07) whereas the albumin increased (p < 0.05) quadratically. Taken together, the optimal dietary CP levels for growth performance of Huanjiang mini-pigs from 5- to 10-kg, 10- to 20-kg, and 20- to 30-kg were 18.42, 16.70, and 14.00%, respectively.

Effects of Dietary Protein Levels on Fecal Amino Acids Excretion and Apparent Digestibility, and Fecal and Ileal Microbial Amino Acids Composition in Weaned Piglets.

Background and Aims: The purpose of this study was to determine the effects of low protein diets with the same Lys, Met + Cys, Thr, and Trp levels as in high protein diets on the fecal amino acid excretion and apparent digestibility, and ileal and fecal microbial amino acids composition in weaned piglets.Methods: Fifty-four 21-day-old Duroc × Landrace × Yorkshire weaned piglets were randomly divided into three groups and fed with corn-soybean meal basal diets, in which the crude protein (CP) content was 20% (H-CP), 17% (M-CP), and 14% (L-CP), respectively. The experiment included a 7-day adaptation period and a 45-day trial period. Six piglets in each group were randomly slaughtered on days 10, 25, and 45 of the trial period, and the intestinal contents, intestinal mucosa, and feces were collected.Results: The results showed that the interaction between feeding time and dietary CP levels was reflected in the apparent digestibility of dietary CP and amino acid (AA) (p < 0.01). With the increase of age, the apparent digestibility of CP and AA were increased (p < 0.01). With the increase of CP levels, the excretion of nitrogen (N) was decreased (p < 0.01), whereas the flow of microbial AA in the ileum and feces were increased (p < 0.01). The interaction between feeding time and dietary CP levels was also reflected in the composition of AA in the ileum and stool of piglets (p < 0.01). The proportion of His, Lyr, Met, Cys, and Ser was lower than the average, whereas the proportion of Phe, Leu, Pro, Ala, Glu, and Asp was higher than the average. With the increase of age, the AA content of microorganisms increased (p < 0.01).Conclusion: All in all, this work revealed the changes of N, CP, and AA excretion and digestibility of feces and microorganisms of piglets under the combined action of different dietary protein levels and different feeding times, and also the changes of AA composition of intestinal microorganisms and AA composition of microorganisms.

Increasing dietary crude protein levels attenuates the effects of caecotrope deprivation in growing rabbits

The effect of caecotrope deprivation on growth, caecal metabolism and Volatile Fatty acid (VFA) production was studied in rabbits fed varying levels of dietary protein during a 42-days feeding trial. Fourty-eight mixed breed rabbits (average initial weight = 875±25 g) were divided into two groups viz; caecotrope consuming (CC) and caecotrope-deprived (CD) groups. Rabbits in the 2 groups were divided equally and assigned to 3 diets containing different crude protein (CP) levels (12, 15 and 18%) in a 2 × 3 factorial arrangement. The result revealed that increasing dietary CP improved (P&lt;0.05) the proximate composition of the caecotrope. The live weight, weight gain, feed conversion ratio, nitrogen utilization and VFA production in CD rabbits fed diets containing 18% CP were comparable (P&lt;0.05) with those of CC fed diets with 15% CP. Nitrogen utilization increased (P&lt;0.05) following increasing dietary crude protein level. Molar proportions of acetate, butyrate, and propionate were higher (P&lt;0.05) in CC rabbit compared to CD. Lactobaccilus acidophilus was isolated from the caecum of CC rabbits. It was concluded that caecotrope deprivation has detrimental effect on growth, nitrogen metabolism, VFA production and caecal bacteria and this effect can be attenuated by increasing the dietary protein level in growing rabbits.

Dietary protein levels during the pullet phase (8–18 week) influence the mortality during laying stage

An experiment was conducted to evaluate the effects of dietary crude protein levels on growth performance, serum and bone parameters, production performance, and egg quality of Hy-Line brown chicken. A total of 384 pullets were randomly allotted to one of 3 groups with 8 replicates of 16 birds each and were fed with a diet containing 14% crude protein (CP), 16% CP, or 18% CP from 8 to 18 wk. At 18 k, 8pullets from each treatment were randomly selected and sampled. The results showed that the dietary treatment did not influence the feed intake, FCR (growth performance), body weight, and body composition at the end of the pullet phase; however, at 30 wk, BW was decreased (P < 0.05) in the 14% CP group compared to other groups. At 18 wk, the dietary treatment did not influence serum concentrations of Ca, P, and calcitonin (CT); however, PTH showed a trend to increase with high protein diet. The dietary CP levels did not influence the bone characteristics. Cumulative egg production was not influenced by the dietary protein levels. Mortality during the laying period was significantly higher in the low CP group. It was concluded that a low protein diet during the rearing phase did not affect the femur and tibia parameters at the end of the pullet phase and production performance but increased mortality during the laying period.

Protein-sparing effect of dietary lipid: Changes in growth, nutrient utilization, digestion and IGF-I and IGFBP-I expression of Genetically Improved Farmed Tilapia (GIFT), reared in Inland Ground Saline Water

Protein-sparing by lipid helps in conserving protein exclusively for growth with minimal inevitable protein breakage. It will subsequently reduce feed cost and nitrogenous pollutants in the habitat. In this context, an experiment of 60 days period was conducted to study the protein-sparing effect of lipid in the diet of Genetically Improved Farmed Tilapia (GIFT) (Oreochromis niloticus L) fingerlings reared in inland ground saline water (IGSW) at 10 g L−1 salinity. The experiment followed 4 × 2 factorial design with eight purified diets of four crude protein (CP) levels (30%, 35%, 40% and 45%), each with two lipid levels (6% and 10%). GIFT fingerlings of uniform size (3.00 ± 0.01 g) were acclimatized and distributed into eight treatment groups in triplicates corresponding to each of the prepared diets and fed to satiation three times daily. The results showed significantly (p < 0.05) higher percent weight gain (WG, 693.26%), apparent net protein utilization (ANPU, 34.03), protein efficiency ratio (PER, 2.35) and improved digestive enzymes (protease, amylase, lipase) activity with lower feed conversion ratio (FCR) for diets containing 35–45% CP and 10% lipid. According to two-way ANOVA, high dietary lipid (10%) resulted highest WG% (678.95), PER (2.02), ANPU (30.67) and lowest FCR (1.31) values. Increased whole body CP (15.54%) and lipid (7.61%) contents were observed in the fish fed high lipid (10%) diets. The viscerosomatic and hepatosomatic index also increased with increasing dietary lipid. The dietary CP levels have not significantly affected the body composition except total ash content. The highest insulin like growth factor-I (IGF-I) gene expression was observed in the liver of fish fed 35% CP with 10% lipid. Results revealed that increasing dietary lipid exhibited enhanced protein-sparing effect in GIFT fingerlings. Thus, the study concludes that a diet containing 35% CP and 10% lipid is optimal for GIFT fingerlings reared in IGSW of 10 g L−1 salinity.

EFFECT OF DIFFERENT PROTEIN AND/OR METABOLIZABLE ENERGY LEVELS IN DIETS FORMULATED BASED ON IDEAL PROTEIN CONCEPT ON PERFORMANCE, EGG PRODUCTION, AND EGG QUALITY TRAITS OF LAYERS DURING PHASE 1 OF EGG PRODUCTION

A comparative study was conducted to determine the impacts of crude protein (CP) reductions in laying hen diets. During phase one of egg production, 270 laying hens were randomly assigned into six dietary treatments, which were replicated three times using a 2 × 3 factorial experiment. Reduced CP and metabolizable energy (ME) diets were formulated based on the ideal amino acid profile concept and supplemented with crystalline amino acids. The control treatment received standard commercial diets containing 18.8% CP and 2,725 kcal/kg ME. Average weight gain, hen day egg production percentage, egg weight, egg mass, and other selected egg quality parameters were recorded. Data were statistically analyzed. Feed consumption and the feed conversion ratio were improved in birds fed reduced CP diets supplemented with crystalline amino acids. The dietary CP level significantly influenced shell thickness (ST), while the dietary ME level had no effect. A highly significant interaction was observed between CP percent and the Haugh unit (HU). Results indicate that the “ideal protein concept” may be followed as an economically feasible option for laying hens since it optimizes the dietary amino acid profiles and ME levels, and have a positive effect on hen growth, egg quality and environmental pollution.

293 Effect of Supplementing Rumen-protected Methionine on Blood Parameters and Ruminal Metabolites in Lactating Holstein Dairy Cows

Abstract The aim of the present study was to evaluate the effects of reducing dietary crude protein (CP) levels and supplementing rumen-protected methionine (RPM) on blood parameters and ruminal metabolites in lactating Holstein dairy cows. A total of 30 lactating Holstein dairy cows (60 ± 7 d in milk; mean ± SD) were randomly assigned to 1 of 2 treatments: diet containing 17.3% CP without RPM (control group; CON); diet containing 16.4% CP with supplementing 15.0 g/d of RPM (treatment group; RPM). All repeated, continuous data were subjected to PROC MIXED procedure of SAS (SAS version 9.2, SAS Institute Inc., Cary, NC.). The results related to blood showed that cows in RPM group exhibited lower concentration of blood urea nitrogen than that in CON group (P &amp;lt; 0.001). Moreover, there were no differences among treatments on concentrations of aspartate transaminase, alanine transaminase, alkaline phosphatase, globulin and albumin (P &amp;gt; 0.05). In ruminal metabolites, microbial CP (MCP) of dairy cows in RPM group was higher compared with CON group (P = 0.006). The concentrations of butyrate, valerate and isovalerate of RPM group were higher than that of CON group at 2h after feeding (P &amp;lt; 0.05). In conclusion, lower dietary CP with RPM supplementation could improve nitrogen utilization of dairy cows and synthesis of MCP in rumen, as well as change volatile fatty acids production at 2h after feeding.

294 Effect of Supplementing Rumen-protected Methionine on Production, Apparent Digestibility and Economic Effectiveness in Lactating Holstein Dairy Cows

Abstract The aim of the present study was to evaluate the effects of reducing dietary crude protein (CP) levels and supplementing rumen-protected methionine (RPM) on production, apparent digestibility of nutrients and economic effectiveness of lactating Holstein cows. A total of 96 (60 ± 7 d in milk; 34.39 ± 5.74 kg/d of milk production; mean ± SD) lactating Holstein dairy cows were randomly assigned to 1 of 2 treatments: diet containing 17.3% CP without RPM (control group; CON); diet containing 16.4% CP with supplementing 15.0 g/d of RPM (treatment group; RPM). All the data were analyzed using one-way analysis of variance (ANOVA) of SAS (SAS version 9.2, SAS Institute Inc., Cary, NC.). No effects were observed of reducing dietary CP on somatic cell counts, milk yield and milk composition including fat, protein, lactose, total solid, solids-not-fat and milk urea nitrogen. The total apparent digestibility of nutrients was similar between treatments, while RPM group had higher calcium digestion (44.24% vs. 42.75% ± 10.13%) and phosphorus digestion (48.50% vs. 45.96% ± 12.90%) numerically. In addition, supplying the diet of 16.4% CP with RPM supplementation to cows could reduce feeding cost by 0.5 $/d per cow and boost net profits. In conclusion, lower dietary CP with RPM supplementation did not limit milk yield, milk composition and apparent digestibility of nutrients, and also could improve the economic benefits of the dairy farms.

Dietary protein requirement of juvenile spotted knifejaw Oplegnathus punctatus

A dietary strategy was conducted with graded crude protein (CP) levels (various from 27.08% to 58.10%) in six semi-purified diets to investigate the appropriate dietary CP supplement for juvenile spotted knifejaw (Oplegnathus punctatus). Experimental diets were respectively offered to the juvenile fish with three replicates (18 individuals each replicate, 19.91 g fish-1) for 8-week. After the feeding trial, the weight gain (WG) was improved by increment of dietary CP levels, but deteriorated slightly when dietary CP over 45.87%. The daily feed intake (DFI) elevated as dietary CP decreasing. Besides, the lowest protein efficiency ratio (PER) and feed efficiency (FE) were observed in 27.08% CP treatment. However, the PER and energy retention (ER) were not significantly different among 32.97%, 39.71% and 45.87% CP groups. In the current study, fish fed diet with 58.10% CP obtained slightly lower PER and nitrogen retention (NR), but relatively higher lipid retention (LR) value compared to those fed a diet with 45.87% CP. And the daily nitrogen intake (DNI) in the fish fed on the low CP levels (27.08 to 39.71%) were significantly lower than that in 45.87% CP treatment. The various dietary treatments did not differ in the visceral index (VSI), hepatosomatic index (HSI) and serum glucose, but fish in the lowest CP group had a decreased intraperitoneal fat ratio (IPF). The protein content in the whole body and dorsal muscle of the fish significantly elevated with dietary protein increasing. The aspartate transaminase (AST) in serum increased with increasing dietary CP from 27.08%-52.65 and then decreased. The regression analysis in second order polynomial and two slope broken-line mode based on NR and WG indicated that the optimal protein supplement for juvenile O. punctatus is 42.92%-46.44%. The present study also indicated that O. punctatus had poor ability to utilization dietary carbohydrate.

Production efficiency, milk yield, and milk composition and fatty acids profile of lactating goats feeding formaldehyde-treated canola meal in two levels of dietary crude protein

The effectiveness of formaldehyde treated canola meal (FTCM) in two levels of dietary crude protein (CP) were evaluated in an experiment. Eight multiparous lactating Raini goats (early lactation, 32 ± 2 kg BW) were used in a 4 × 4 Latin square design with four treatments. Experimental diets were: (1) diet with 14.5 % CP containing untreated canola meal (UCM) (CON), (2) diet with 14.5 % CP containing FTCM (0.8 g/100 g CP) (FT1), (3) diet with 14.5 % CP containing FTCM (1.2 g/100 g CP) (FT2), and (4) diet with 12.5 % CP containing FTCM (1.2 g/100 g CP) (LPFT2). Dry matter intake (DMI) of the goats was significantly increased by substitution of FTCM in the diet (P < 0.001). Feeding FT2 and LPFT2 diets significantly increased production of milk, fat-corrected milk (FCM), energy-corrected milk (ECM), total-solids-corrected milk (TSCM) (P < 0.001), and yields of fat, protein, lactose, total solids, and non-fat solids (P < 0.01). However, dietary treatments did not affect milk composition of the goats. Production efficiency for milk and FCM were highest (P < 0.001) in goats fed the LPFT2 diet. Moreover, the FT1 diet decreased C4:0, C6:0, C8:0, C10:0, C12:0, C15:0, C17:0, t-C18:3, and total short-chain and long-chain fatty acids (FA) of the milk (P ≤ 0.01), but C16:0 and total medium-chain FA were increased (P ≤ 0.01) as compared to CON and FT2. Although formaldehyde treating did not affect ruminal pH, the concentrations of ruminal ammonia-N (NH3-N), and blood urea-N (BUN) decreased by feeding FT2 and LPFT2 diets (P < 0.001). Also, LPFT2 diet increased concentration of total ruminal VFA (TVFA) and showed lower acetate/propionate ratio when fed to the goats (P < 0.05). In general, substitution of 1.2 % FTCM had improved feed intake and productive performance of lactating goats; it is therefore concluded that formaldehyde treating of canola meal can be used as an economical choice for increasing dietary bypass protein, by which the level of diet crude protein can be reduced.

High-level dietary crude protein decreased backfat thickness and increased carcass yield score in finishing Hanwoo beef cattle (Bos taurus coreanae).

Recently, a high level of dietary crude protein (CP) has become of interest as a possible practice to improve the carcass quality of beef cattle, and its level has been increasing in the field. However, there is little scientific evidence that supports this. This study was conducted to test whether a high dietary CP level would improve growth performance, body metabolism, and carcass traits in Hanwoo beef cattle. A total of 32 Hanwoo finishing beef cattle (18 multiparous cows, six heifers, and eight steers) participated in a 12-weeks feeding trial. Two kinds of total mixed rations were prepared to contain two different CP; 156 g/kg for the control (CON) and 173 g/kg of CP for the treatment (HCP), while maintaining a similar level of metabolizable energy. The experiment was ended when more than half of the steers reached the target body weight (730 kg). Blood was collected at the end of the experiment. After harvesting, the carcass trait was evaluated at the slaughterhouse according to Korean standards. The carcass yield score and grade were also calculated based on revised criteria. Overall, dry matter intake, average daily gain, blood metabolites concentration, and the carcass traits, except for backfat thickness and the yield score, did not differ between the treatments. The HCP had lower backfat thickness than those of CON. There was no difference in the carcass yield grade, but the yield score was higher in the HCP treatment. According to the newly revised carcass grading criteria, both yield score and grade were higher in HCP than in CON. Increasing CP supply decreased the carcass’s backfat thickness without altering growth performance and body metabolism, resulting in improved yield score and grade. Therefore, feeding a high CP diet may be beneficial in the farm income, although it may also increase feed cost and nitrogen excretion to the environment.

The effects of pharmacological levels of zinc, diet acidification, and dietary crude protein on growth performance in nursery pigs.

This experiment was conducted to evaluate potential replacements for pharmacological levels of Zn (provided by Zn oxide), such as diet acidification (sodium diformate) and low dietary crude protein (CP: 21 vs 18%) on nursery pig performance and fecal dry matter (DM). A total of 360 weaned pigs (Line 200 × 400, DNA, Columbus, NE; initially 5.90 ± 0.014 kg) were used in a 42-d growth study. Pigs were weaned at approximately 21 d of age and randomly assigned to pens (five pigs per pen). Pens were then allotted to one of eight dietary treatments with nine pens per treatment. Experimental diets were fed in two phases: phase 1 from weaning to day 7 and phase 2 from days 7 to 21, with all pigs fed the same common diet from days 21 to 42. The eight treatment diets were arranged as a 2 × 2 × 2 factorial with main effects of Zn (110 mg/kg from days 0 to 21 or 3,000 mg/kg from days 0 to 7, and 2,000 mg/kg from days 7 to 21), diet acidification, (without or with 1.2% sodium diformate), and dietary CP (21% or 18%, 1.40% and 1.35% in phases 1 and 2 vs. 1.20% standardized ileal digestible Lys, respectively). Fecal samples were collected weekly from the same three pigs per pen to determine DM content. No 2- or 3-way interactions (P > 0.05) were observed throughout the 42-d study for growth performance; however, there was a Zn × acidifier × CP interaction (P < 0.05) for fecal DM on day 7 and for the overall average of the six collection periods. Reducing CP without acidification or pharmacological levels of Zn increased fecal DM, but CP had little effect when ZnO was present in the diet. From days 0 to 21, significant (P < 0.05) main effects were observed where average daily gain (ADG) and gain:feed (G:F) increased for pigs fed pharmacological levels of Zn, sodium diformate, or 21% CP (P < 0.065). In the subsequent period (days 21 to 42) after the experimental diets were fed, there was no evidence of difference in growth performance among treatments. Overall (days 0 to 42), main effect tendencies were observed (P < 0.066) for pigs fed added Zn or sodium diformate from days 0 to 21, whereas pigs fed 21% CP had greater G:F than those fed 18% CP. Pig weight on day 42 was increased by adding Zn (P < 0.05) or acidifier (P < 0.06) but not CP. In summary, none of the feed additives had a major influence on fecal DM, but dietary addition of pharmacological levels of Zn or sodium diformate independently improved nursery pig performance.

Dietary crude protein levels during growth phase affects reproductive characteristics but not reproductive efficiency of adult male Japanese quails.

ObjectiveThe objective was to evaluate the influence of different dietary crude protein (CP) levels during the growth phase on reproductive characteristics and reproductive efficiency as well as the body development of adult male Japanese quail.MethodsThree hundred one-day-old male quails were distributed into five treatments with diets containing different CP levels (18%, 20%, 22%, 24%, and 26%) in a completely randomized design, with six replicates of ten birds each. The CP diets were applied only during the growth phase (1 to 35 days). At 36 days of age, the birds were transferred to 30 laying cages with three males and nine females each, and all birds received the same diet formulated to meet production-phase requirements until 96 days of age.ResultsThe growth rate of the birds increased linearly (p<0.01) with increasing dietary CP, but the age of maximum growth decreased (p<0.05). At growth maturity, all birds had the same body weight (p>0.05). At 35 days of age, higher weight gain was obtained (p<0.05) with diets containing 22% CP or higher. No effects on feed conversion were observed in this phase. The increase in dietary CP enhanced (p<0.01) nitrogen intake and nitrogen excretion but did not affect (p>0.05) nitrogen retention. Testis size, seminiferous tubular area, number of spermatogonia, and germinal epithelial height at 35 days of age increased linearly (p<0.05) with dietary CP, while the number of Leydig cells decreased (p<0.01). The Sertoli cell number at 60 days of age increased linearly (p<0.01) with dietary CP. Dietary CP levels did not affect cloacal gland size, foam weight, foam protein concentration, semen volume, or flock fertility at 90 days of age.ConclusionDietary CP concentration affected body and testicular development in male Japanese quails but did not affect reproductive efficiency.

Impact of Microbial Protease Enzyme and Dietary Crude Protein Levels on Growth and Nutrients Digestibility in Broilers over 15–28 Days

Simple SummaryProtein is considered as the most expensive nutrient in animal diet and requires exogenous proteolytic enzymes for proper digestion in all living organisms. Thus, the present study evaluated different crude protein levels (CP) with or without exogenous protease in broilers diet over 15–28 days on their growth and nutrient digestibility. Based on the obtained findings, it is recommended a reduction in protein contents of diets from 21 to 19% when the protease enzyme is supplemented, to produce a beneficial impact on the growth and digestibility of broilers and also to reduce feeding costs.In this trial, a 3 × 2 factorial design with different dietary crude protein levels (CP, 17, 19 and 21%) and two levels of exogenous protease (0 and 30,000 IU/kg) was used. A total of 540 two-week old broilers (Ross-308) was randomly allocated to experimental diets over 15–28 days of age. The interaction between dietary protein levels and enzyme supplementation showed that body weight gain was significantly (p < 0.05) higher in birds fed CP-19 (1114.7 g) and CP-21 (1108.8 g) with enzymes supplementation. Feed intake was higher (p < 0.05) in broilers fed with CP-17 than CP-19 with supplementation of the protease enzyme. Results also revealed that the feed conversion ratio (FCR) was significantly (p < 0.05) improved in birds fed with CP-19 and CP-21 and protease supplementation. Total tract N retention was lower (p < 0.05) in birds fed CP-17 with no enzyme than the other dietary groups. Similarly, the gross energy (GE) was significantly (p < 0.05) lower in birds fed CP-17 with or without the protease enzyme. Abdominal fat was higher (p < 0.05) in CP-17 (0.96%) without the protease enzyme. It was concluded that a diet at 19% CP with the protease enzyme improved the performance and nutrient digestibility in broilers over 15–28 days.

Nitrogen balance, production performance, and plasma metabolites of lactating buffaloes in response to varying dietary protein levels.

Protein imbalance in dairy rations affects N balance and milk N efficiency (MNE) resulting in extra N excretion to the environment. The objective of this study was to investigate the changes in N balance, milk production, and plasma metabolites of lactating buffaloes in response to different dietary crude protein (CP) supplies. Six multiparous Nili Ravi buffaloes in mid-lactation were used in this experiment in a 3 × 3 Latin square design. The treatments were diets with 9.26, 10.0, and 11.4% of CP on DM basis. All the diets were iso-caloric (2.05 Mcal metabolizable energy/kg of DM), whereas oat silage was mixed with the respective concentrate and offered once daily as total mixed ration. Milk fat content and yields of actual milk, 4% fat corrected milk, milk fat, protein, and lactose increased by 3.97, 9.63, 11.8, 6.23, and 6.57%, respectively. Milk protein content tended to increase linearly with increasing dietary CP levels. Milk N secreted as g/d increased, while as percent of N intake decreased. The resulting decrease in MNE (13.7%) was 3.45 greater than the increase in milk yield observed by increasing dietary CP from 9.26 to 11.4% of DM. Total manure N increased linearly in terms of g/d and tended to increase as percent of N excreted. Excretion rate of N also increased linearly by 32%. In conclusion, milk yield, milk fat, protein, and lactose yields increased; however, decreased MNE indicates relatively greater N losses as observed by increased N excretion rate when CP level increased from 9.26 to 11.4% in the diet of lactating buffaloes.