Analysis of fattening effects in Zhedong white geese at different ages

[Análise dos efeitos da engorda em gansos brancos de Zhedong em diferentes idades]

ABSTRACT

To explore the impact of age on the fattening effects in Zhedong white geese, this experiment selected 240 geese to undergo a three-week fattening period starting at 49 d and 70 d. The results showed that the final weight and feed-to-gain ratios (F/G) in the first and second weeks were significantly higher in the geese that started fattening at 70d compared to those starting at 49d (P<0.05). The F/G ratio in the third week was significantly lower in the 70d group compared to the 49d group (P<0.05). Additionally, the weights of the breast muscle, leg muscle, abdominal fat, intestinal fat, gizzard pH, and heart were significantly higher in the 70d group (P<0.05). The meat color L values and b* values of the breast and leg muscles were higher in the 70d group, while the leg muscle pH was significantly higher in the 49d group (P<0.05). Overall, the analysis suggests that starting fattening at 70d can improve the final weight and slaughter performance of Zhedong white geese but also increases the F/G ratio and reduces carcass quality and meat color. Therefore, the fattening effects are superior when started at 49d.

Keywords:
growth performance; meat quality; organ indexes; Zhedong white geese

RESUMO

Para explorar o impacto da idade sobre os efeitos da engorda em gansos brancos de Zhedong, este experimento selecionou 240 gansos para serem submetidos a um período de engorda de três semanas, com início aos 49 e 70 dias. Os resultados mostraram que o peso final e as relações de alimentação/ganho (F/G) na primeira e segunda semanas foram significativamente maiores nos gansos que começaram a engordar aos 70 dias em comparação com os que começaram aos 49 dias (P<0,05). A relação F/G na terceira semana foi significativamente menor no grupo de 70 dias em comparação com o grupo de 49 dias (P<0,05). Além disso, os pesos do músculo do peito, do músculo da perna, da gordura abdominal, da gordura intestinal, do pH da moela e do coração foram significativamente maiores no grupo de 70 dias (P<0,05). Os valores L da cor da carne e os valores b* dos músculos do peito e da perna foram maiores no grupo de 70 dias, enquanto o pH do músculo da perna foi significativamente maior no grupo de 49 dias (P<0,05). Em geral, a análise sugere que o início da engorda aos 70 dias pode melhorar o peso final e o desempenho no abate dos gansos brancos Zhedong, mas também aumenta a relação F/G e reduz a qualidade da carcaça e a cor da carne. Portanto, os efeitos da engorda são superiores quando iniciada aos 49 dias.

Palavras-chave:
desempenho de crescimento; qualidade da carne; índices de órgãos; gansos brancos de Zhedong

INTRODUCTION

In the various stages of meat goose growth and development, the fattening period is the most crucial. During this time, the goose's bones, muscles, and feathers undergo rapid growth and maturation, and the body's capacities gradually strengthen. Therefore, good feed nutrition is vital for the meat quality and subsequent growth of the geese (Nemati et al., 2020). Protein plays multiple roles, including immune function, support, protection, and cell structure (Di Gioacchino et al., 2022), and the crude protein level in the feed during the fattening period is controlled at about 20% (Alagawany et al., 2022). However, merely pursuing high protein content is not always beneficial, as the utilization rate of protein by animals is influenced by various factors, including protein quality and energy supply (Gilani et al., 2005). If the diet is high in protein but low in energy, this can lead to protein wastage, and animals may adjust their energy intake by altering their feed consumption (Baile and Forbes, 1974).

The Zhedong white goose is a high-quality local breed in China, known for its superior meat quality and unique flavor, and is highly favored by consumers. With the rising living standards, there are increasing demands for meat quality (Ouyang et al., 2022). Zheng et al. analyzed the amino acid and fatty acid composition and content of Zhedong white geese at different ages, finding that the content of polyunsaturated and essential fatty acids significantly decreases with age, and there are significant differences in the total amino acids and umami amino acids content at different ages (Zheng et al., 2013). Huang et al. (2016) have examined the basic composition, fatty acid composition, free amino acid composition, volatile aromatic components, and texture characteristics of Tianfu white geese at different ages. Xie et al. (2012) have studied the patterns of inosine monophosphate and intramuscular fat deposition in Yangzhou geese and their hybrid combinations, finding that muscle quality differs significantly among geese of different ages (Xie et al., 2012; Huang et al., 2016). It is evident that the poultry's age and market timing can greatly affect muscle quality and breeding costs (Bu et al., 2018), making the appropriate fattening period and market age crucial for breeding efficiency and product quality. However, reference materials related to meat goose breeding are currently lacking and do not meet production needs. This study aims to explore the fattening effects of Zhedong white geese at different ages, providing a theoretical basis for optimal fattening and market timing.

MATERIALS AND METHODS

All animal procedures were performed according to guidelines provided by the China Council on Animal Care. All animal experiments were approved by the Animal Care and Use Committee of West Anhui University (SYXK, Wan 2021-009).

The experiment was conducted at the Zhanghang Experimental Station Goose Farm of the Shanghai Academy of Agricultural Sciences. Zhedong white geese were sourced from the Zhejiang Eastern White Goose Research Institute in Xiangshan County. For the experiment, physically healthy geese with similar body weights were raised normally until day 49, at which point they were divided into two groups, each with six replicates, consisting of equal numbers of males and females. The first group (2953.48±179.53) began a three-week fattening period immediately, while the second group (3845.33±121.24) was raised normally until day 70 before starting their three-week fattening period. The geese were floor-raised, with free access to water and feed, and received standard vaccinations. The formal experimental period lasted three weeks.The diets of groups at the fattening stage were consistent, and the specific nutrient levels were shown in Table 1.

Table 1
Composition and nutrient level of experiment diets (air-dry basis)

Items	Content (%)	Nutrient level2	Content (%)
Ingredients		CP	16.00
Corn	67.92	ME (MJ/kg)b	12.40
Soybean meal	24.90	CF	2.56
Soybean oil	2.00	Ca	0.79
Lys	0.09	P	0.51
Met	0.09	Lys	0.90
Thr	0.00	Met	0.45
Premix1	5.00	Thr	0.63
Total	100.00	Cys	0.21

• ¹
  One kilogram of the premix contained the following: Fe 100 mg, Cu 8 mg, Mn 120 mg, Zn 100mg, Se 0.4 mg,Co 1.0 mg, I 0.4mg, VA 8330 IU, VB1 2.0mg, VB2.8mg, VB6 1.2 mg, VB12 0.03mg, VD31440 IU, VE 30IU, biotin 0.2 mg,folic acid 2.0mg, pantothenic acid 20mg, niacin acid 40mg.
• ²
  CP (Crude protein), ME (Metabolizable energy), CF (Crude fiber)

Throughout the experiment, from start to finish, the geese were weighed on an empty stomach weekly to calculate the weight gain (ADG). Daily before 08:00, the amount of feed added was weighed, and the leftover feed was weighed again at 20:00 each day to calculate the average daily feed intake (ADFI). Using the ADG and ADFI, the feed-to-gain ratio (F/G) was calculated.

At the end of the experiment, the geese were euthanized by cervical dislocation, with efforts made to minimize pain during sampling. Measurements and calculations of slaughter traits were performed following the methodology of Zhai et al. (2020). According to the "Determination of Livestock and Poultry Meat Quality" (NY/T 823-2004), a colorimeter (Chroma Meter CR-410, Konica Minolta Corporation, Japan) was used to measure the color of the breast and leg muscles. The tissue pH was measured using a Testo-205 pH-measuring instrument.

Data recorded was entered into Excel 2016, and after organizing and preprocessing, the experimental data were analyzed using SPSS version 20.0. Duncan's multiple range test was used for post-hoc comparisons. A significance level of P < 0.05 was used to determine the statistical significance of differences.

RESULTS

Results from Table 2 reveal significant differences in body weight between fattened and normal geese (P<0.05), indicating that fattening significantly enhances the final weight of geese. Furthermore, the initial and final body weight of geese started on fattening at 70 days are significantly higher than those started at 49 days (P<0.05). However, total weight gain in the 70-day group was significantly lower than in the 49-day group. During the fattening period, the F/G ratio in the 49-day group increased weekly, while it began to decrease in the third week for the 70-day group. The F/G ratios for the first and second weeks in the 70-day group were significantly higher than those in the 49-day group (P<0.05), but significantly lower in the third week (P<0.05). This suggests that while fattening at 70 days can significantly enhance the productive performance of geese, it also increases the F/G ratio.

Table 2
Effects of different fattening days on the growth performance of Zhedong white geese in the trial period

Groups	Initial body weight, g	Final body weight, g	Total gain weight, g	First week F/G	Second week F/G	Third week F/G
49d	2953.48± 179.53b	4023.15± 189.48b	1070.49± 83.22a	3.89± 0.49 b	7.69± 0.77b	9.63± 0.73a
70d	3845.33± 121.24a	4861.66± 97.43a	1016.32± 120.50b	4.62± 0.67a	10.46± 0.91a	6.56± 0.97b

• ^{a, b}
  Different letters superscripts mean significant differences (P < 0.05).

As per Table 3, the age at the onset of fattening affects the slaughter performance of geese. The carcass weight and clean carcass weight of the geese that began fattening at 70 days were significantly higher than those that started at 49 days (P<0.05). Weights of abdominal fat and intestinal fat were also significantly higher in the 70-day group (P<0.05), suggesting that fattening at this age can improve slaughter performance but also leads to an increase in fat deposits, potentially reducing carcass quality.

Table 3
Effects of different fattening days on the slaughter performance of Zhedong white geese

Groups	Carcass weight, g	Full bore weight, g	Chest muscle weight, g	Leg muscle weight, g	Abdominal fat weight, g	Intestinal fat weight, g
49d	3489.49± 153.08b	2817.82± 199.89b	174.56± 56.35b	166.15± 18.71b	78.09± 24.85b	50.96± 4.84b
70d	4372.16± 148.29a	3515.50± 141.20a	185.00± 28.07a	237.66± 16.53a	109.83± 22.78a	54.66± 13.21a

• ^{a, b}
  Different letters superscripts mean significant differences (P < 0.05).

From Table 4, it is evident that the age at fattening does not significantly affect the weight of major internal organs such as the gizzard, glandular stomach, and pancreas between the two groups (P>0.05), although heart weight was significantly higher in the 70-day group (P<0.05), indicating no detrimental effect on most internal organ weights due to fattening at 70 days.

Table 4
Effects of different fattening days on the internal organs of Zhedong white geese

Groups	muscle stomach pH	muscle stomach weight, g	glandular stomach weight, g	pancreas weight, g	heart weight, g
49d	3.17± 0.42	121.41± 9.03	13.12± 1.53	12.02± 5.16	34.72± 4.54b
70d	3.00± 0.82	143.00± 19.81	13.83± 0.98	12.75± 1.70	43.66± 3.88a

• ^{a, b}
  Different letters superscripts mean significant differences (P < 0.05).

Table 5 shows the impact of fattening age on breast muscle quality, where the L* and b* values of the breast muscle in the 70-day group were significantly higher than those in the 49-day group (P<0.05). Water-holding capacity, shear force, and pH values showed little difference between the groups. Similar to breast muscle, the L* and b* values of the leg muscle in the 70-day group were significantly higher than in the 49-day group (P<0.05). However, the leg muscle pH was significantly higher in the 49-day group compared to the 70-day group, with no significant differences in other indicators (P>0.05). This suggests that while certain quality parameters of muscle improve with fattening age, others like pH maintain consistent levels regardless of the age at fattening.

Table 5
Effects of different fattening days on muscle quality of Zhedong white goose

Groups	L*Value	a*Value	b*Value	water loss rate(%)	shear force(kg.f)	pH
breast muscle
49d	35.13±2.09B	11.02±1.25	7.59±1.30B	7.87±1.26	7.38±0.51	6.11±0.37
70d	42.03±1.16A	10.72±1.81	8.89±1.48A	8.19±1.90	6.77±0.50	5.78±0.20
leg muscle
49d	38.88±2.42b	11.61±1.12	9.23±0.59	11.42±2.85	8.13±2.74	6.52±0.31a
70d	41.42±2.06a	11.58±1.10	10.10±0.76	9.44±1.85	7.93±1.29	6.19±0.32b

• ^{a, b}
  Different letters superscripts mean significant differences (P < 0.05).

DISCUSSION

Growth performance is a critical indicator of animal production and is considered one of the most important economic traits. Goose meat is known for its tender, soft texture, and distinctively fresh flavor without being greasy. It is not only delicious but also characterized by low fat and cholesterol content, making it highly popular among consumers. However, geese in the mid-fattening stage tend to have lower body weights, limited body fat deposition, and inferior meat quality, often accompanied by a certain grassy taste. Short-term fattening before market can enhance the quality of geese, achieving a goal of well-fattened, tender meat with high edible value. Studies have shown that fattening during periods when meat ducks have fully developed digestive functions and skeletal structures can significantly increase feed intake and weight gain, allowing them to be marketed earlier (Wang, 1999). Research has demonstrated that using phased feeding techniques for fattening piglets can achieve reduced feed costs (Wu, 2022). After 8 weeks, the growth rate of Magang geese slows down, with body length growth gradually decreasing after 7 weeks, and submersible length and neck length growing faster in the initial 7 weeks. Measurements of actual body weight and body size traits show that by 49 days, the skeletal structure of meat geese is essentially formed, allowing the start of fattening to increase muscle and fat mass (Tang et al., 2021). This aligns with our study, where geese started on fattening at 49 days exhibited significantly lower weight gain compared to those started at 70 days, although feed conversion efficiency was notably lower.

Slaughter performance is an important economic indicator for evaluating poultry. From the results of this study, it is evident that the slaughter weight, clean carcass weight of geese fattened for 70 days are significantly higher than those fattened for 49 days, which correlates with their respective growth periods. At the same time, the weights of abdominal fat and intestinal fat also show significant differences, likely because the body organs of geese at this stage are mostly mature, metabolism slows down, and the liver's capacity to synthesize fat increases. The abdomen is a crucial site for fat deposition in animals, generally related to breed, sex, and environmental factors, and the amount of abdominal fat deposited also varies during different growth periods of the animal (Yang et al., 2015). Studies have found that the growth and development pattern of goose organs from fastest to slowest is liver > intestines > leg muscles > skin fat > feet > abdominal fat > gizzard > wings > breast muscle (Liang et al., 2007). It can be observed that the growth and development of the breast muscle primarily occur later, which is similar to the results of this study.

Muscle quality has always been another economic indicator of great concern for poultry and is an important criterion for consumers purchasing high-quality meat. Water-holding capacity, shear force, pH, and meat color are critical indicators for evaluating meat quality (Wu et al., 2008). A decrease in muscle water-holding capacity can lead to the release of cellular fluids, causing the muscle surface to become moist and increase the reflection of natural light, increasing the L value and decreasing the a value (Zhang et al., 2018). Research indicates that meat consists of fats, proteins, various trace elements, and vitamins, and is influenced by multiple factors. Age is a significant factor affecting meat quality. Zheng et al., (2015) found significant differences in the intramuscular fat content of mule ducks at different ages, which significantly increased with age, and age had a significant effect on cooking loss, shear force, water-holding capacity, and b* value of the muscle. Ji et al., (2007) analyzed the impact of slaughter age on the quality of breast muscle in dwarf yellow chickens, finding that slaughter age had a minimal impact on muscle pH value but primarily affected meat quality as intramuscular fat content increased with age. Similar to these findings, this study observed that the L and b values of the breast and leg muscles of geese started on fattening at 49 days were lower than those of geese at 70 days, indicating that the meat color of 49-day-old geese is superior to that of 70-day-old geese.

CONCLUSION

Overall, the analysis suggests that starting fattening at 70d can improve the final weight and slaughter performance of Zhedong white geese but also increases the F/G ratio and reduces carcass quality and meat color. Therefore, the fattening effects are superior when started at 49d.

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Publication Dates

• Publication in this collection
  21 Feb 2025
• Date of issue
  Mar-Apr 2025

History

• Received
  19 July 2024
• Accepted
  11 Sept 2024