Crude Protein Levels Research Articles

Effects of dietary protein content on the productive and reproductive performance of unselected rabbit does and their litters during first two lactations

The aim of the present study was to evaluate the influence of different dietary protein levels on the productive performance of unselected rabbit does and their litters during their first two lactations. For this purpose, fifty-two nulliparous rabbit does, 4.5 months of age and live weight of 3115 ± 71 g, were divided into three groups (17 or 18 females per group), kept in individual cages and each group received only one of the three experimental diets. These diets were iso-energetic (10.8 MJ DE/kg), but with increasing levels of crude protein (CP): 15%, 17% and 19 % for the low (L), medium (M) or high (H) diets, respectively. Breeding was carried out by natural copulation using 6 males of 5-6 months of age and 2865±21 g initial weight, controlled semi-intensive lactation and weaning at 35 days after birth. Female body weight, feed intake, milk production, litter size and weight were monitored at birth and weekly after parturition during the first two lactations. The protein intake of the rabbits increased with the amount of protein in the diet (L vs. M: +12.2%; L vs. H: +18.8%; p < 0.001), without any effect on milk production and feed intake. Milk production was unaffected by parity. Throughout the pre-weaning period, litter size and weight and maternal mortality were unaffected by dietary protein level. Dietary protein level had no effect on live weight, birth to weaning weight gain, milk production or feed intake during the first two consecutive lactations of rabbit does.

Dietary metabolizable energy and crude protein levels affect Taihe silky fowl growth performance, meat quality, and cecal microbiota during fattening

The effects of dietary metabolizable energy (ME) and crude protein (CP) on the growth performance, meat quality, and cecal microbiota of Taihe Silky Fowl (TSF) during fattening were investigated. In total, 900 twelve-week-old female fowl were randomly allocated to 9 treatments (5 replicates per group, 20 fowl per replicate), and were fed a 3 × 3 factorial arrangement of treatments diets (ME: 11.30, 11.93, or 12.56 MJ/kg; CP: 15%, 16%, or 17%). As ME increased, the average daily feed intake (ADFI, P<0.001), feed conversion ratio (FCR, P<0.001), pectoral and thigh shear forces (P<0.05), pectoral and thigh muscle fiber diameter (P<0.001) decreased significantly, while muscle fiber density increased (P<0.001). Pectoral muscle fiber diameter was lower and muscle fiber density higher at 16% CP than 15% or 17%. As ME increased, pectoral crude fat content increased significantly (P = 0.007). Pectoral crude protein, total amino acid (TAA), and essential amino acid (EAA) content were higher at 15% dietary CP than 16% or 17%. As ME increased, pectoral inosine monophosphate (IMP, P = 0.006), uridylic monophosphate (UMP, P = 0.003), guanylic monophosphate (GMP, P = 0.009), and adenosine monophosphate (AMP, P <0.001) decreased significantly, while hypoxanthine riboside (HxR, P = 0.045) increased. As dietary CP increased, IMP (P = 0.019), AMP (P <0.001), and HxR (P = 0.024) increased significantly. Cecal microbiota composition varied with dietary ME: 12.56 MJ/kg ME increased the abundance of Bifidobacteriaceae, and 15% CP increased that of Paraprevotella. These findings suggest that 12.56 MJ/kg dietary ME and 15% CP can enhance growth performance, improve meat quality by reducing shear force, enhancing flavor and nutritional value, and benefit for intestinal microbiota in fattening TSF.

Comparative study of mash vs pellet feed on growth performance and feed utilization by goat

This study was conducted in Bharatpur-11, Chitwan, Nepal, to evaluate the effects of two feed forms (mash and pellet) on the growth performance and feed utilization in goats. Twenty Boer cross female goats, averaging five months in age, were assigned to either mash or pellet feed treatments, with 10 goats in each group, for a 90-day period, with two weeks of adaptation. The experimental animals were given concentrate feed at 1% of their body weight daily, along with ad libitum access to Napier grass and clean drinking water. Both feed types had a dry matter content of 90% and a crude protein level of 17%. Key parameters assessed included feed and forage intake, body weight changes, and feed wastage. Goats on pelleted feed showed a significantly higher average daily weight gain of 62.00 g/day compared to 26.11 g/day for those on mash feed. Final body weights were also greater in the pellet-fed group (28.88 kg) compared to the mash-fed group (25.04 kg). Additionally, pelleted feed led to higher intake of concentrate and forages and significantly reduced feed wastage, with pellet feed waste being 1.22 g/day versus 27.65 g/day for mash feed. These findings indicate that pelleted feed enhances growth performance, feed intake, and feed efficiency in goats. Therefore, this study indicated that pelleted feed is a more effective option for enhancing goat productivity and reducing feed wastage.

469 Reducing crude protein levels with amino acid supplementation in the finishing diets of heavy Duroc sire line pigs: Effects on carcass and meat traits in males and females

Abstract Nutrition represents 70% of pig production costs, particularly protein; therefore, decreasing protein costs is of capital importance. Reducing crude protein (CP) contents to levels below recommended whilst supplementing with amino acids (AAs) is an interesting strategy to reduce costs without decreasing production performances. It has been conducted essentially in lean genotypes during the growth stage. Few studies address heavy genotypes or sex differences during the finishing period. Our objective is to study carcass and meat (loin) traits of heavy [Duroc X (Landrace X Large-White)] male and female pigs during the finishing stage under a 2% CP reduction with crystalline AA supplementation, hypothesizing that both sexes will be affected equally. In total, 60 males and 60 females, 9 wk old animals were used and allotted in split-sex pens (6 pigs/pen) with water and dry feed ad libitum. At 15 wk of age, when pigs weighed an average of 68 kg, two isoenergetic diets with different CP levels were provided (145 and 125 g CP/kg, control and low-CP) during the last 42 d of fattening. In the low-CP diet, crystalline AAs were added. On last day of the trial, animals weighed 116.5 kg on average and were slaughtered. Hot carcass weights and yields, ham fat thickness, lean meat percentage and boar taint by human nose scoring were determined. Loin samples (one per pen) were used to determine thawing losses, pH, color, Texture Profile Analysis (TPA: hardness, cohesiveness, springiness) and chemical composition (moisture, ash, protein, collagen, fat, and saturated fat). Data were analyzed using the simple least squares models that included dietary treatment and sex and their interaction as fixed effects with the pen as the experimental unit. Carcass weights were greater in control males than in females (91.2 vs 85.7 kg; P &amp;lt; 0.05). No effect of sex or diet was detected on carcass yields, lean contents or ham subcutaneous fat thickness. There was a great impact of sex for loin subcutaneous fat thickness, with males having 7 to 8% greater values in both dietary treatments (P = 0.011). Low-CP females had a greater percentage of carcasses of greater lean content compared with the three other groups (P &amp;lt; 0.05). Boar taint, carcass pH, color traits, chemical analysis and TPA did not differ across diets. A strong dietary influence was noticeable with animals of both sexes in the Low-CP diets having greater fat and saturated fat contents than animals in the control groups (P = 0.02). In conclusion, the 20g/kg CP reduction supplemented with AAs can efficiently be used in heavy Duroc sire line genotype during the finishing phase without leading to major impairments in carcass or meat traits, regardless of sex.

470 Reducing crude protein levels with amino acid supplementation in the finishing diets of heavy Duroc sire line pigs: Effects on growth performance and nitrogen balance in males and females

Abstract Nutrition represents 70% of pig production costs, particularly protein; then, decreasing protein costs is of capital importance. Reducing crude protein (CP) contents to levels below recommended whilst supplementing with amino acids (AAs) is an interesting strategy to reduce costs without decreasing production performances with environmental benefits. It has been conducted essentially in lean genotypes during the growth stage. Few studies address heavy genotypes or differences between males and females during the finishing period. Our objective is to study productive performances of heavy [Duroc X (Landrace X Large-White)] male and female pigs during the finishing stage under a 2% CP reduction with crystalline AA supplementation, hypothesizing that both sexes will equally be affected. In total, 60 males and 60 females were used. At 9 wk of age, animals were allotted in split-sex pens (6 pigs/pen, 0.9 m2/animal) with water and dry feed ad libitum. At 15 wk of age, when pigs weighed an average of 68 kg, two isoenergetic diets with different CP levels were provided (145 and 125 g CP/kg, control and low-CP) during the last 42 d of fattening, under the ideal protein concept. In the low-CP diet, crystalline AAs were added. Feed intake was measured daily, and animals were weighed every 3 wk to calculate average daily feed intake (ADFI), average daily gain (ADG), feed conversion ratio (FCR) and N balance on d 21 and 42. Data were analyzed using the simple least squares models that included dietary treatment and sex and their interaction as fixed effects with the pen as the experimental unit. At d 21, animals weighed 90 to 95 kg with males being 5 to 6 % heavier (P &amp;lt; 0.01). No significant differences were recorded regarding diet. The same difference (P &amp;lt; 0.001) was recorded at day 42, with males (119-122 kg) being 7.25% heavier than females in both treatments. Males had 16% higher ADGs than females in both treatments (P &amp;lt; 0.0001) No differences were recorded for ADFI as a consequence of sex for both diets. FCRs were higher in females of both nutritional treatments (P &amp;lt; 0.0001). Retained N was 22% greater in males than in females for both dietary treatments. The N efficiency was greater in Low CP males by comparison with low CP females and control males, whereas control CP females had decreased N efficiency compared with all other experimental groups. Results demonstrate that the 20g/kg CP reduction supplemented with AAs can efficiently be used in heavy Duroc sire line genotypes during the finishing phase without a decrease in production parameters with females having poorer growth performances than males, whereas N efficiency was impaired when females had no limiting dietary CP.

236 Increased dietary protein supports key metabolic and intestinal tissue functions in weaned pigs, without increasing gastrointestinal pathogen abundance

Abstract A common dietary strategy to prevent diarrhea in weaned pigs is feeding low protein diets in the period immediately following weaning. The goal of this intervention is to decrease dietary protein sufficiently to reduce pathogen proliferation and protein fermentation without negatively impacting growth performance. One potential alternative to low protein diets is provision of dietary fiber. However, many studies examining the role of protein and fiber on gastrointestinal microbiota and post-weaning diarrhea are complicated by the presence of other substrates, including polyphenols and antinutritional factors in complex ingredients. To assess the role of increased protein and fiber on gut microbiota and host metabolism, semi-purified diets differing in crude protein (CP) and crude fiber (CF) were fed to weaned pigs (n = 40; 28 d of age). Diets with high protein (HP; CP 24.3%, CF 6.4%), high fiber (HF; CP 18.9%, CF 9.4%), or both (HFHP; CP 24.9%, CF 9.5%) were compared with a control (CON; CP 18.1%, CF 6.3%) diet with industry standard crude protein and fiber levels (n = 10/group). Growth performance and diarrhea prevalence were measured alongside gut microbiota composition and metabolites. Pigs fed the HP and HFHP diets had significantly improved feed efficiency compared with both CON and HF diets. Increased protein fermentation, measured through production of biogenic amines, was observed in HP fed animals (P &amp;lt; 0.001). These effects were mitigated by addition of fiber in the HFHP fed pigs. Despite increased markers of protein fermentation, post-weaning diarrhea incidence was not greater in HP fed animals and no increases in gastrointestinal pathogen abundance were detected. Metabolomic and transcriptomic analyses identified critical alterations in host metabolism and cecal transcriptome in the CON compared with the HP fed animals. While all diets were formulated to meet the dietary requirements of weaned pigs, diets with lower protein levels (CON and HF) induced alteration in transcripts from the serine synthesis pathways (P &amp;lt; 0.001) and integrated stress response (P &amp;lt; 0.001) in cecal tissue alongside increases in metabolic pathways related to lysine degradation (P = 0.005). These results challenge the current practice of low protein feeding following weaning by demonstrating a detrimental effect of low protein diets on intestinal cell function and muscle accretion. This suggests that with careful ingredient selection, increased dietary protein post-weaning could better support pig health and performance compared with current industry standard diets.

Nutritional prospects and heavy metal risks in fattened versus wild mud crabs of the Ganges-Brahmaputra delta: Implications for sustainable management

Scylla olivacea, or the mud crab, is a crucial economic contributor in Southeast Asia, notably in the coastal region of the Ganges-Brahmaputra delta. This study compared the nutritional and heavy metals of fattened and wild-captured mud crabs from the southwest coastal areas of the Ganges-Brahmaputra delta, focusing on proximate composition, fatty acids, amino acids, and heavy metals. Fattened mud crabs showed higher crude protein levels (13.2%–14.4%), particularly in males, and higher crude fat and ash contents than their wild counterparts. Among fatty acids, fattened crabs had the highest palmitic acid levels (34.0%–41.2%), whereas wild crabs were rich in linoleic and linolenic acids. Amino acid analysis revealed that histidine and arginine were the most prevalent essential amino acids in fattened and wild crabs, respectively. Elemental analysis indicated that calcium levels were high in both groups. However, zinc, copper, iron, and manganese concentrations exceeded recommended dietary allowances. Furthermore, the wild mud crabs contained heavy metals lower than that of the fattened mud crabs. Notably, nickel, lead, and cadmium levels surpassed maximum permissible limits, suggesting potential health risks in fattened and wild mud crabs. The concentration of Omega-3 fatty acids was higher in wild crabs than in cultured ones. These findings emphasize the need for cautious consumption and strict monitoring in mud crab aquaculture to ensure food safety and sustainability.

Effects of Phosphorus Application Levels on Its Uptake and Utilization in Foxtail Millet

Foxtail millet is a traditional minor crop in China, known for its strong resistance to stress, tolerance to barren lands, and wide adaptation. Phosphorus is an essential element for crop growth and development, and the appropriate application of phosphorus can enhance crop yield and quality. However, the optimal phosphorus fertilization levels for the growth of foxtail millet have yet to be determined. This study aims to explore the effects of different phosphorus application levels (T1, T2, T3, and T4), on phosphorus accumulation and use efficiency and crop yield and quality in the foxtail millet cultivars ‘B376’ and ‘B27’, which have different phosphorus efficiencies. Additionally, we investigated the effects of phosphorus accumulation and use efficiency on the heading and filling stages of these cultivars. The results show that the total phosphorus content and accumulation levels in the ‘B376’ and ‘B27’ cultivars vary at different developmental stages and in different plant parts. Furthermore, crop yield and quality in both cultivars vary in response to the different phosphorus application levels. In terms of yield, the phosphorus-tolerant variety ‘B376’ reaches its highest at T2, while the phosphorus-sensitive variety ‘B27’ achieves its maximum yield at T3. For quality, ‘B376’ exhibits the highest moisture and crude fat content under T4, and the highest protein and the lowest amylose content under T3. On the other hand, ‘B27’ achieves its highest moisture content under T4, its highest crude fat and protein levels under T3, and its lowest amylose content under T2. Therefore, the response to different phosphorus application levels differs between the two cultivars with different phosphorus use efficiencies. Moreover, under different phosphorus fertilization levels, the average crop yield, moisture, fat, and amylose content averages of the phosphorus-tolerant ‘B376’ cultivar are 16.1%, 1.2%, 7.0%, and 4.1% higher than those of the phosphorus-sensitive ‘B27’ cultivar. Additionally, phosphorus use efficiency is positively correlated with the moisture and crude fat contents of foxtail millet. In conclusion, the phosphorus-tolerant cultivar demonstrates superior phosphorus accumulation, absorption, and utilization capacities compared to the phosphorus-sensitive cultivar. These results suggest that in the phosphorus-tolerant ‘B376’, optimal phosphorus fertilization levels enhance the development of roots, stems, and leaves at the T2 (P45) level, and promote the accumulation of moisture and crude fat in foxtail millet grains, thereby improving their taste and quality. Our findings provide a theoretical basis for phosphorus fertilizer utilization in foxtail millet cultivation and will help determine the optimal fertilization levels for foxtail millet growth.

Эффективность скармливания поросятам-отъемышам кормов с разным уровнем изолейцина и сырого протеина

В статье приведены результаты использования в кормлении поросят-отъемышей полнорационных комбикормов с разными уровнями изолейцина и протеина, а также с различным соотношением аминокислот с разветвленными боковыми цепями (АРЦ), которые обеспечивают получение 236–308 г среднесуточного прироста в послеотъемный период. В исследованиях установлено, что оптимальным соотношением АРЦ (изолейцин/лейцин/валин) является 100/180/140 для рационов с различным уровнем сырого протеина. The article presents the results of research on the use of complete compound feeds in the nutrition of weaning piglets with different levels of isoleucine and protein, and a different ratio of branched-chain amino acids (BCAA), which make it possible to obtain average daily gains in the post-weaning period — 236–308 g. The results of the study suggest that the optimal ratio of BCAA (isoleucine/leucine/valine) is 100/180/140, for diets with different levels of crude protein.

Different dietary branched-chain amino acid ratios, crude protein levels, and protein sources can affect the growth performance and meat yield in broilers

Balanced ratios of branched-chain amino acids (BCAAs) can enhance chicken growth, immunity, and muscle synthesis. However, these ratios can be affected by changes in crude protein (CP) levels or the substitution of protein sources, leading to BCAA antagonism. This, in turn, can have a negative impact on chicken growth. In Experiment 1, a total of 960 0-d-old male Cobb 500 broilers were divided into 6 treatments with 8 replicates. Three different BCAA ratios were used in High or Low CP diets as follows: 1) Low Leu group (Low level of leucine with increased valine and isoleucine levels), 2) Med Leu group, and 3) High Leu group (High level of leucine with reduced valine and isoleucine levels) for a total of 6 diets. In Experiment 2, a total of 640 0-d-old male Cobb 500 broilers were divided into 4 treatments with 8 replicates. The four diets had either High or Low CP and one of two protein sources with the same medium levels of BCAAs: 1) the soybean meal (SBM) group, which had SBM as the main protein source (protein bound AA), and 2) the wheat middlings with non-bound AAs (WM+AA) group (non-bound AA), which had additional non-bound AAs to replace SBM. The High Leu diet had a negative effect on overall growth performance, carcass weight, breast muscle weight, and body mineral composition compared to the Low Leu and Med Leu groups, particularly in the High CP diet (P < 0.05). The SBM group showed increased growth performance, breast muscle weight, expression levels of genes promoting muscle growth, and improved bone mineral composition compared to the WM+AA group, and the High CP group intensified the negative effect of the WM+AA diet (P < 0.05). In summary, balanced BCAA ratios and SBM-based diets have positive effects on chicken growth and muscle accretion, whereas excessive leucine and non-bound AA levels in the diets may negatively affect growth performance and meat yield in chickens.

Annual and seasonal dry matter production, botanical species composition, and nutritive value of multispecies, permanent pasture, and perennial ryegrass swards managed under grazing

AbstractReduced reliance on inputs such as fertilizer is fundamental to sustainable grazing systems. This two‐year study compared four sward types, including multispecies swards (MSS), for herbage dry matter (DM) production, species contribution to DM, and herbage nutritive value under grazing. The systems were: (1) Lolium perenne L. monoculture (PRG; 170 kg N ha−1 year−1); (2) permanent pasture (PP; 135 kg N ha−1 year−1), (3) six species sward consisting of two grasses, two legumes and two herbs (6S; 70 kg N ha−1 year−1), (4) twelve species sward consisting of three grasses, four legumes and five herbs (12S; 70 kg N ha−1 year−1). Herbage samples were collected for DM yield, botanical composition, and nutritive value. Mean annual DM production for PRG, PP, 6S, and 12S was 11,374, 8526, 13,783, and 13,338 kg DM ha−1 respectively. Herb proportions decreased in 6S and 12S from 2020 to 2021 while grass proportions increased. Mean crude protein levels were similar across all systems (p &gt; 0.05), with higher ash content in 6S and 12S compared to PRG (p &lt; 0.001). Organic matter digestibility was lowest in PP compared to PRG (p &lt; 0.001) while neutral detergent fibre content of PP and PRG were greater than 6S and 12S (p &lt; 0.001). Water soluble carbohydrate content was highest in PRG (p &lt; 0.0001). Over 2 years, MSS delivered increased herbage DM yield and nutritive quality relative to PRG and PP swards, from reduced N inputs. However, maintenance of the herb component of MSS is a challenge.

PSXII-25 Impacts of crude protein level and urea source on finishing performance of Nellore bulls

PSXII-25 Impacts of crude protein level and urea source on finishing performance of Nellore bulls

Impact of lowering nitrogen content in pig manure through low crude protein diets on anaerobic digestion process stability, biogas yields, and digestate composition

Lowering crude protein in pig diets can reduce nitrogen (N) excretion and alter manure characteristics. Anaerobic digestion (AD) offers potential for converting pig manure into biogas and bio-based fertilizers (i.e., digestate). However, limited research exists on the effects of N content in pig manure on AD when pigs are fed diets with varying crude protein levels. This study investigated how lowering N content in pig manure through low crude protein diets may affect AD process stability, biogas generation, and digestate properties. Manures from different dietary treatments, named as control (CON), low N (LN), and very low N (VLN), with Total Kjeldahl Nitrogen concentrations of 5.87, 5.42, and 5.15 g/L, respectively, were investigated. Daily biogas production, composition (CH4, CO2, and H2S), and digestate properties were monitored over 13 fed-batch cycles (25 ± 4 days per cycle). The experiment was conducted at 20 ± 1 °C, a condition suited for milder climate regions, using six single-stage digesters operated in sequencing fed-batch mode. Data were analyzed by ANOVA using PROC MIXED with repeated measures. Results showed that the differences in N content in pig manure due to the three dietary treatments had a limited impact on biogas generation, with specific methane yields remaining similar over time. CH4 concentrations remained stable between 60 and 65 %, ensuring high-quality biogas despite dietary variations. Differences between treatments became more pronounced with increased organic loading rates (OLRs) due to variations in the amount of volatile solids fed. AD also remained stable (Total Volatile Fatty Acids/Total Alkalinity <0.25) even at an OLR of 2.15 g of chemical oxygen demand L−1 day−1, highlighting AD's robustness at lower temperatures. Digestate samples contained essential minerals beneficial for plant growth. More research is needed to explore varied manure compositions and feeding strategies to better understand the interactions of animal nutrition with AD.

Determination of feed value of chemically treated sun-dried grape pomace

This study aimed to elucidate the effects of various chemical treatments on the in vitro dry matter digestibility (IVDMD) and concomitant feed value of dried grape pomace (DGP). Sun-dried grape pomace, derived from grapes processed in Denizli, Türkiye province was used in the experiment. One control group and three treatment groups were established, each with eight replicates. The first, second and third experimental groups were treated with 1.5% ammonia (NH3), 3% urea (CH4N2O) and 3% sodium hydroxide (3%) (NaOH), respectively. The dry matter content was set at 50% for all groups. The control group received no additional chemicals. All groups were kept in airtight, closed plastic bags at room temperature for one week. Adding NH3 and CH4N2O significantly improved crude protein levels (24.45 and 19.84%, respectively) and in vitro protein degradability (59.84 and 65.69%, respectively) in the experimental groups (p

Nutritional, safety, and starch properties of flour from selected sweet cassava (Manihot esculenta Crantz) varieties grown in Nakuru County Kenya

Cassava plays a critical role in food security, particularly in sub-Saharan Africa due to its drought-resistant nature, high-yielding potential, and multipurpose application. This study analyzed ten cassava varieties recently introduced in Nakuru County, Kenya for their proximate composition, mineral content, anti-nutritional factors, and starch digestibility. The results showed significant variations in these factors among the varieties. The main component of cassava flour was total digestible starch, accounting for approximately 84.86 %, with low levels of crude fat and protein. Cassava flour showed low calcium, iron, and zinc levels, and a wide variation in phytates, potentially reducing their bioavailability. All the flour from the ten cassava varieties met safety limits for cyanide levels <10 mg/kg, with the Selele variety having the lowest cyanide. The starch analysis showed higher levels of Slowly Digestible Starch (41.1–53.0 %) and lower levels of Rapidly Digestible Starch (29.5–36.0 %). Cassava flour also showed significant levels of resistant starch ranging between 4.56 % and 7.23 %, supporting its beneficial impact on human health. The study provides valuable insights for cassava breeders to develop targeted nutritional qualities and empowers consumers to make informed choices.

Optimal glycine allowance levels in low-protein diets and the dynamic requirement model for broilers

This study aimed to investigate the effects of different glycine levels in low-protein diets on the growth, nitrogen deposition, and expression of intestinal amino acid and glucose transporters in broilers from 29 to 42 days of age, in order to determine the optimal glycine supplementation level. A total of 240 male broilers at 29 days old were randomly assigned to 5 groups: the control group with a crude protein level of 20%, and experimental groups with low-protein diets (LP130) containing 18% crude protein, supplemented with glycine to achieve standardized ileal digestible (SID) glycine + serine to lysine ratios of 134% (LP134), 140% (LP140), and 145% (LP145). The results showed that the LP134 group had similar growth performance and slaughter performance compared to the control group (P > 0.05), whereas other low-protein diet groups had significantly lower growth performance (P < 0.05). Regression analysis determined that the optimal ratio for SID glycine + serine to lysine was 137%. A dynamic model for glycine + serine requirements was established through binary regression analysis: y = 599.051 × BW^0.75 + 8.381 × ADG (R2 = 0.998, P < 0.001). Feeding LP134, LP140, and LP145 diets significantly improved nitrogen deposition rates in broilers (P < 0.05). Low-protein diets significantly upregulated mRNA levels of b0,+AT, EAAT3, and SGLT1 genes in the duodenum (P < 0.05). In conclusion, appropriate glycine supplementation in low-protein diets can enhance growth performance, and nitrogen deposition efficiency, and regulate the expression of intestinal amino acid and glucose transporters. The optimal ratio of SID glycine + serine to lysine in low-protein diets for broilers aged 29 to 42 days is 137%.

Oxidative stress markers in brain and gonads of rabbit bucks fed herbal supplements

BackgroundCurrently, there is an increase in the usage of phytogenic feed additives to help improve animal welfare and productivity, while less emphasis is now placed on metabolic and oxidative stability of neuronal and testicular tissues. This study aims at investigating the effects of Moringa oleifera, Phyllanthus amarus and Viscum album as feed additives on some metabolic indicators and oxidative status of rabbit testis and brain. Isonitrogenous and isocaloric diets were formulated with 5% supplementation of each of the phytogenic additive to 3 treatment groups and basal diet group.ResultsIt was revealed that moringa, mistletoe, and phyllanthus can modulate oxidative status in both the brain and gonads of rabbit bucks through their unique phytochemical compositions, thereby affecting reproductive and cognitive functions. Moringa, rich in crude protein, saponins, glycosides, and steroids, enhances protein and lactate dehydrogenase levels but increases lipid peroxidation in the testis. Mistletoe, with high crude fiber, ash, and antioxidants like flavonoids and tannins, boosts total antioxidant activity in several brain regions and reduces lipid peroxidation, indicating its potential for reducing oxidative stress. Phyllanthus, having the least fiber and ash but effective antioxidant properties, notably affects the oxidative balance in both the testis and brain, with varied impacts on different tissues. The result obtained showed that total antioxidant activity of the left testis was enhanced (p < 0.05) by inclusion of the phytogenic additives, while total antioxidant activity of the right testis in bucks fed on phytogenic additives were similar (p > 0.05) to bucks on basal diet. Bucks fed on moringa and phyllanthus additives had higher (p < 0.05) testicular lipid peroxidation, lowered testicular protein and/or lactate dehydrogenase. Result also shows that lipid peroxidation of hypothalamus, cerebrum, olfactory lobe and cerebellum were lowest in bucks fed on mistletoe, phyllanthus, phyllanthus and phyllanthus, respectively. High catalase activity of optic lobe, olfactory lobe and cerebellum were observed in bucks fed on mistletoe, moringa and mistletoe, respectively, while glutathione peroxidase activity in hypothalamus, cerebrum, olfactory lobe and pineal was enhanced (p < 0.05) in bucks fed on moringa and mistletoe compared to bucks on other treatment.ConclusionM. oleifera, P. amarus and V. album leaves as phytogenic feed additives in rabbit diets have negative effect on the metabolic activity of the testis, enhancing antioxidant activity in the brain.

Morphological Differentiation, Yield, and Cutting Time of Lolium multiflorum L. under Acid Soil Conditions in Highlands.

Livestock production in the basins of the northern macro-region of Peru has as its primary source pastures of Lolium multiflorum L. 'Cajamarquino ecotype' (ryegrass CE) in monoculture, or in association with white clover Ladino variety, for feeding. The objective of this research work was the morphological characterisation, yield evaluation, and cutting time evaluation of two local genotypes (LM-58 and LM-43) of Lolium multiflorum L. in six locations. An ANOVA was performed to compare fixed effects and interaction. It was determined that the LM-58 genotype is intermediate, growing semi-erect, with a dark green colouring and 0.8 cm broadleaf, and can reach an average stem length of 46 cm, up to 1.6 cm. day-1, achieving fourth-leaf growth at 28 days under appropriate management conditions. Despite the differentiated characteristics, according to BLASTn evaluation, the ITS1 sequences showed a greater than 99.9% similar identification to Lolium multiflorum L., characterising it as such. It was determined that the LM-58 genotype outperforms LM-43, achieving a forage yield of 4.49 Mg. ha-1, a seed production of 259.23 kg. ha-1, and an average of 13.48% crude protein (CP). The best biomass yield (49.10 Mg. ha-1.yr-1) is reached at 60 days; however, at 30 days, there is a high level of CP (14.84%) and there are no differences in the annual protein production at the cutting age of 60 and 45 days. With the results of the present study, LM-58 from a selection and crossbreeding of 680 ryegrass EC accessions emerges as an elite genotype adapted to the conditions of the northern high Andean zone of Peru.

Optimization of dietary protein based on ideal protein concept for genetically improved farmed tilapia (GIFT) juveniles reared in inland saline water

A 60-day feeding trial was performed to optimize dietary protein based on the ideal protein concept for genetically improved farmed tilapia (GIFT) juveniles reared in inland saline water (ISW) of 10 ppt salinity. Seven heteronitrogenous (373.6–256.5 g crude protein/kg), isocaloric (∼ 16 MJ digestible energy/kg) and isolipidic (∼ 80 g lipid/kg) semi-purified feeds were formulated and prepared with decreasing levels of crude protein (CP), namely 373.6 (CP1), 352.2 (CP2), 334.5 (CP3), 314.9 (CP4), 293.7 (CP5), 275.2 (CP6) and 256.5 g/kg (CP7). The proportion of total essential and semi-essential amino acids was kept constant in all diets as ideal amino acid profiles and total non-essential amino acids were reduced linearly to reduce the dietary CP levels. Three hundred fifteen juveniles (average weight 4.76 ± 0.01 g) were randomly assigned into seven groups in triplicate. Fish of various groups were fed thrice daily at an apparent satiation level. The growth of juveniles increased linearly and quadratically (p<0.05) when the CP level of diets was decreased from 373.6 (CP1) to 334.5 g/kg (CP3), then declined linearly. The CP2 and CP3 groups had significantly higher feed intake and lower feed conversion ratio. In contrast, low CP-fed groups had superior protein utilization, viscerosomatic index and hepatosomatic index than other groups. The CP1 and CP2 groups had significantly higher whole-body protein and lower lipid content. The whole-body non-essential amino acid content diminished linearly (p<0.05) as dietary CP levels were decreased; the whole-body essential amino acid content remained unchanged (p>0.05). The high CP-fed juveniles (CP1 and CP2) showed a significantly (p<0.05) elevated protease activity, whereas the opposite trend was noticed for amylase activity. The aminotransferase activities of the liver and muscle were reduced linearly (p<0.05) with reduced dietary CP levels. Serum glucose and cholesterol contents elevated linearly (p<0.05) with decreased dietary CP levels. Whereas, the hemoglobin content and RBC count decreased (p<0.05) in the high CP-fed juveniles. The second-order polynomial regression analysis revealed that the optimal dietary CP levels could range from 311.1 to 318.0 g/kg for GIFT juveniles reared in ISW of 10 ppt salinity. Furthermore, by adopting the ideal protein concept, the CP levels in the diet of GIFT juveniles could be reduced from 373.6 to 311.1 g/kg without affecting growth performance. The outcome of this study will assist in developing a low-protein feed with balanced essential amino acids for GIFT culture in ISW.

Effects of dietary protein level on liver lipid deposition, bile acid profile and gut microbiota composition of growing pullets

The current study investigated the effects of dietary crude protein (CP) level on the liver lipid metabolism, gut microbiota, and bile acids (BA) profiles of growing pullets. Roman growing pullets (N = 180, 13-wk-old) were divided into 3 treatments groups with 6 replicates in each group and 10 hens in each replicate and provided 3 different dietary CP level diet treatments. The diet treatments included: a high-protein diet (15.5% CP, HP group), a medium-protein diet (14.5% CP, MP group), and a low-protein diet (13.5% CP, LP group). Compared with HP group, LP group significantly increased the lipid contents in the body (such as Breast intramuscular fat [BIMF], Leg intramuscular fat [LIMF], Percentage of abdominal fat [PAF], liver triglyceride [TG] and liver cholesterol [TC]), and the lipid metabolism-related parameters in serum (such as cholesterol (TC), high density lipoprotein cholesterol [HDL-C], low density lipoprotein cholesterol [LDL-C], very low density lipoprotein [VLDL]), and the mRNA expression of lipid metabolism-related genes (such as fatty acid synthase [FAS], CCAAT/enhancer binding protein β [C/EBPβ], and fatty acid translocase [FAT/CD6]) (P < 0.05). In addition, LP group significantly reduced the contents of lithocholic acid (LCA), isoLCA, and ursodesoxycholic acid (UDCA), and increased the deoxycholic acid (DCA) content compared with HP group (P < 0.05). The effects of LCA on lipid deposition were confirmed in chicken preadipocyte cell line (CPI), in which LCA supplementation significantly decreased the relative expression of PPARγ, FAS, acyl-CoA carboxylase (ACC) and SREBP-1c (P < 0.05). Correlation analysis further revealed a significant association between BA profiles and lipid metabolism-related parameters. Furthermore, 16S rRNA gene sequencing indicated that dietary protein level can significantly affect the richness, diversity, and composition of cecal microbiota in growing pullets. LP group significantly increased the abundance of Bacteroidetes and significantly decreased the abundance of Firmicutesa compared with the HP group. In summary, low protein diet in growing pullets influence the liver lipid metabolism through changing the gut microbiota and liver BA metabolism.